LIBRARY OF CONGRESS. 

iSWjtt — 

©top. J. - Gajnjng^t Ifo 

Shelf J^A* 

UNITED STATES OF AMERICA. 



PRIMARY 



MICROSCOPY 



—AND- 



BIOLOGY. 



A TEXT BOOK 

FOR THE USE OF STUDENTS IN 

HIGH SCHOOLS, NORMAL SCHOOLS AND 
ACADEMIES, 

j 

ALBERT SCHNEIDER, M. D. 



"VcMeat quomt/u/m valen potest." 



FAIRBURY, ILL., 

Tin: Blade Printing OppiOB. 

1890. 



QH3>7 



CLIFTON SCOTT, B. S., M. D., 

Instructor of Natural Sciences in the Northern 
Illinois Normal School, 

THIS WORK IS DEDICATED. 

IX admiration of 

His Abilities as Teacher and in Remembrance 

of Many Acts of Kindness shown to the 

Author while a Pupil under 

His Guidance. 




Entered according to Act of Congress, in the year 1891, by 

ALBERT SCHNEIDER, M. D., 
In the Office o»f the Librarian of Congress, at "Washington. 









PREFACE 



This work is intended to acquaint the student with the 
elements of Microscopy and Biology. It is not complete in 
any of its parts. It is presented for the purpose of meeting 
a demand in our more elementary institutions of learning, 
and to create a desire in the student to investigate Nature 
and its Laws for himself. The course of study as laid down 
in our public schools, normal schools and academies is such 
that one can not become a master in the field of biology. 
Those who do not have unlimited time and a well lined purse 
to carry on scientific investigations, can only hope to acquaint 
themselves with the rudiments and first principles as present- 
ed in this little work. Afterward, if desirable, they can con- 
tinue in some first-class college or investigate for themselves. 

The student before entering upon this' work is supposed 
to have mastered the elements of chemistry and physics, 
and also geometry and trigonometry. The laboratory work 
is so arranged as to save both time and extra labor. 

Microscopy. — Here are presented the construction and 
uses of the simple and compound microscopes, the formation 
of images and the refraction by lenses, etc. Some hints on 
the purchasing and care of a good microscope. Much could 
have been added which would however only have been tire- 
some to the beginner. 

Biology* — A brief introduction gives the student some 
idea of the extent of this field of investigation, but he should 



not allow this to discourage him. The different steps are so 
arranged as to make clear to the student what he is expected 
to do. He is earnestly advised not to rely too much on the 
outline, but to investigate and reason for himself the " why" 
and "wherefore" of every step he takes. 

There is a purpose in the arrangement of this work. 
The various steps are not placed as if by chance. Therefore 
the student should not omit anything. 

The author will feel amply repaid if he has aided in 
creating in his fellow student a love for the study of Biology. 

A, Schneider. 
Dixon, Aug. 30, 1890. 



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Page 12.... 


Page 13 


Page 16.... 


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Page 27 


Page 31 ... . 


Page 33.... 


Page 46.... 


Page 51 — 


Page 57 


Page 59 


Page 72.... 


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:rrata. 



For "phylosophy" read ''philosophy". 

For "refractoin" read "refraction". 

Fig. 6, top a' should be a. 

In Article 38, Proportion 5, introduce -flHG- 

For "triblet" read "triplet". 

For "trible" read "triple". 

For "trible" read "triple". 

For "miccometer" read "micrometer'*. 

For "olear" read "clear". 

For "evist" read "exist". 

For "Denterostomata" read "Deuterostomata". 

For "mowers" read "mouers". 

For "animal" read "vegetable". 

For "nmbticellular read "multicellular". 

P'or "chitnous" read "chitinous". 

For "No. 2 SO," read "Na 2 SO s ". 

For "Eotasium" read "Potassium". 

For "Tartarate" read •'Tartrate". 



CHAPTER I. 

MICROSCOPY. 



(1) MICROSCOPES. — (Gr., mihros, small; and skopein, to 

view.) 

Objects which are too small to be seen by the naked eye 
are brought into view by an instrument called a microscope. 
The simple microscope was the first to come into use. A 
simple microscope consists of a single lens or a system of 
lenses by means of which the object is viewed directly. The 
time and manner of its discovery is not definitely known. 
There is no doubt that the ancients were acquainted with its 
use. Ptolemy in his "Optics" gave a table of the refractive 
indices for glass and his results agree quite closely with those 
of to-day. 

The discovery of the microscope may have been by acci- 
dent or by design. It is known that Jacharias Jansen & Son 
constructed microscopes as early as 1590. In the year 1685, 
Stellati gave a minute description of the bee which he could 
only have done with the aid of the microscope. By its means 
Leeuwenhoek made his wonderful discoveries. In 1673 he 
discovered red globules in blood. In 1677 he discovered in- 
fusoria in stagnant water. His microscopes were so con- 
structed that he required a new one for every two or three 
objects. 

From the time of Jacharias Jansen till the construction 
of corrected lenses many forms of microscopes were pro- 
duced by scientists and opticians of Italy, France, Germany 
and England. They used only one kind of glass in the man- 
ufacture of their lenses. The holders for these lenses were 
of all descriptions and forms. The great hindrance to the 
perfection of the simple microscope was spherical and chro- 
matic aberration. About 1815 Wollaston and Frauenhot'er 



6 MICROSCOPY. 

gave their attention to the improvement of these defects. 
They used two kinds of glass having different refractive in- 
dices, namely crown and flint glass. Euler made an achro- 
matic objective in 1776. When the greatest magnifying 
power of the simple microscope, consistent with the greatest 
possible correction for spherical and chromatic aberration 
had been obtained, it was believed by scientists and opticians 
that the climax in microscopy had been reached. Even after 
the invention of the compound microscope such men as Wol- 
laston and Biot predicted that the simple microscope could 
not be excelled by the compound. It is not definitely known 
when the first compound microscope was made. It could 
certainly not have taken an optician long to comprehend the 
necessary principles for the construction of the compound 
microscope after fully understanding the simple. In the an- 
cient and middle ages scientists were more interested in 
astronomy than in biology, whence it came that the telescope 
preceded the microscope. The principles of construction are 
very much the same in the two. 

In the compound microscope we have a lens, or a combi- 
nation of lenses acting as one lens, forming a real image ; 
this image is further magnified by a second lens or system of 
lenses. In the simplest form only two lenses are necessary ; 
one to form the real image, the second to further magnify 
the real image. We could Lave an indefinite number of sys- 
tems of lenses, each succeeding one magnifying the preced- 
ing real image. By placing the eye in the focus of the up- 
permost system we would see a virtual image of all the sev- 
eral real images The reason why we do not use more than 
two systems is because the image would appear indistinct on 
account of too much light being absorbed in passing through 
so many lenses. 

Only a few years ago microscopes and works, treating on 
microscopy could only be bought by the wealthy, but now 
the wonderful mechanical aids of to-day and the large num- 
ber of dealers in microscopical material has made them com- 
paratively cheap. Bapid strides are being made in the im- 



MICROSCOPY. 



provement of the microscope. Fifty years ago no one would 
have dreamed of the improvements of to-day, and it is to be 
hoped that fifty years hence the microscope of to-day will be 
a thing of the past, for there is nothing seemingly so perfect 
but it may be made more perfect. 



(2) PHYSICS. — (Or. j physike; Z., physica, natural philos- 
ophy.) 

Nearly every person with good eyesight can look down 
the tube of a microscope and view an object which, of course, 
has first been prepared and placed on the stage by an expert, 
but very few know how that image is formed and brought to 
the eye greatly magnified. Some of the laws of optics with 
demonstrations are introduced here that the student may get 
a more thorough understanding of the subject than he would 
from the ordinary high school text-book on philosophy. It is 
true one may become quite skilled in the manipulation of the 
microscope and not know anything about optics. Yet for his 
own benefit and in order that he may be able to satisfy in- 
quisitive semi-scientists he should acquaint himself as far as 
possible with the mechanics and mathematics of lenses and 
mirrors. 



(3) IMAGES. — (Z., imitarii to imitate.) 

An optical image consists of a collection of focal points, 
from which light either really or apparently radiates. When 
we see rays collected from real focal points we have a real 
image. When we see rays collected from apparent focal 
points we have an apparent or virtual image. 

(4) A real image can be projected upon a screen, a vir- 
tual image can not. 

CS) The apparent focal point can exist only as long as 
perceived by the eye. The real focal point can exist indepen- 
dent of the eye. 

(6) Rays diverging before reflection will diverge at the 
same angle after reflection. 



8 MICROSCOPY. 

(7) Rays converging before reflection will converge at 
the same angle after reflection. 

(8) Rays parallell before reflection are parallell after 
reflection. 

(9) Images formed by plane or convex mirrors are al- 
ways virtual. Those formed by concave mirrors may be 
either. 

(10) The general effect of a concave mirror is to pro- 
duce convergence of rays. 

-Hi The general effect of a convex mirror is to produce 
divergency of rays. 

Fig. 1. 
J8 




APPABE3ST OB VIRTUAL IMAGE FORMED BY A PLAXE MFRROR. 

iL.. mirare. to wonder.) 

(12) Let m n in fig. 1 represent a plane mirror and 
A B an object before it. Let the objects position be such 
that the reflected rays will enter the eye at H. From A and 
B let fall perpendiculars on the mirror, produce them till 
a E = A E and b G = B G. Now rays from A will seem 
to radiate from the apparent focus a., and all those from B at 
b., and all intermediate points between A and B will seem to 
focus at similar points between a. and b. Therefore the ob- 
ject and image are equally distant from the mirror. 



MICROSCOPY. 9 

A C and a c are equal because they are two perpendic- 
ulars between two parallel lines, B6 = b6 and A E = a 
E, therefore by substitution and subtraction B C = b c; the 
angles AC B and a c b are equal because they are both 
right angles, hence A B = a b and B A C — b a c; that 
is, the image by a plane mirror is equal in size, equidistant 
and equally inclined with the object. 

(13) Changing the position of the eye does not change 
the position of the image by a plane mirror. 



Fig. 2. 




CONJUGATE FOCI. 



(14) When rays which radiate from a point are reflect- 
ed by a concave or convex mirror they are again brought to 
a real or apparent point. These points are interchangable 
and are called conjugate foci. 

If the radius of the mirror and the distance of one focus 
are given the distance of the other focus may be determined. 



(15) 



In fig. 2, let radius of mirror 



r; the distance of 



one focus A E = m, and the other focal distance a E = n. 



The angle A B a is bisected by C B. Therefore A B 
: a B : : A C : a C, but since B E is very small, A E : a E : : 
A C : a 0. Substituting, 



10 



MICROSCOPY. 



(1) 'm : n : : m — r : r — n. 

(2) m r — m n = rn n — n r. 

(3) m r — 2 m n= — n r ; or, — m r + 2 m n = n r. 

(4) 2 m n — m r = n r ; or, m (2 n — r) = n r. 

(&) m= 



(6) n 



2 n— r 

m r 
2 m — r. 



Q. E. D. 
Q. E, D. 



Fig. 3. 




/c 



IMAGE BY A CONCAVE MIRROR. 



(16) In a concave mirror when the object is placed be- 
tween the center of curvature and the principal focus the 
image is real, inverted and enlarged. It is real because the 
image can be projected on a screen. It is inverted because 
the axes cross between the conjugate foci. It is enlarged 
since it subtends the angle of the axes at a greater distance 
than the object. d b bisects abc, .\ ad*dc::ab:bc. 
As b c is greater than b a so is d c greater than ad. ad and 
d c measure the distances of object and image from the cen- 
ter of curvature. 

Note. — Other problems in concave and convex mirrors 
should be assigned for demonstration. 



MICROSCOPY. 11 

LENSES.— (Z., lens, a lentil) 

(17) A lens is a transparent medium having at least one 
curved surface. The most common forms are six in number 
shown in fig. 4. 

Fig. 4. 




(18) A, A double convex lens has a common base and 
two' equally or unequally convex surfaces. 

(19) B, A plano-convex lens has one side convex, the 
other plane. It is simply a segment of a sphere or half of 
a double convex lens. 

(20) C, The meniscus or convexo-concave lens has one 
surface concave, the other convex. The convexity exceeding 
the concavity. 

(21) A, B and C have the general effect of double con- 
vex lenses. 

(22) D, A double concave lens has two equally or un- 
equally curved surfaces. 

(23) E, The plano-concave lens one surface plane the 
other concave. 

(24) F, The concavo-convex lens has one surface con- 
vex, the other concave, the concavity exceeding the convexity. 

25) I), E and F have the general effect of double con- 
cave lenses. 

Note. — It is supposed that the student understands the 
general effect upon light on passing through the various 
lenses. 

(26) Lenses of today are nearly all made of crown and 
flint glass. Crown and Hint have different refractive indices 
and are used in order to correct spherical and chromatic aber- 
ration as will be explained further on. 



12 MICROSCOPY. 

REFRACTION. — (Z., re, back, and frcmgere, to break.) 

(27) Refraction is the change in direction that a ray of 
light undergoes in passing from one medium into another. 

(2S) The angles of incidence and refraction are on op- 
posite sides to the perpendicular of the surface. 

(29) In the same media the ratio of the angles of inci- 
dence and refractoin are the same for all inclinations of the 
ray. 

Fig. 5. 




(30) In fig. 5 A C is refracted to E and a C to e, so that 
AD:EF::ad:ef, then by inversion E F . A D : : e f : 

a d. 

(31) This constant ratio is called the index of refraction. 
It is found by dividing the sine of the angle of incidence by 
the sine of the angle of refraction. 

Let i = index of refraction. Then i —— =— = ^ 

sine h E 

(32) When the ray of light passes from air or some 
other medium into the substance it gives the comparative 
index. 



MICROSCOPY. 



13 



When the ray of light passes from a vacuum into the sub- 
stance it gives the absolute index. 

(33) The following table gives the absolute indices of 
refraction : 



Diamond 2 45 

Carbon Disulphide 1.69 

Oil of Cassia 1.63 

Flint Glass (mean) 1.6 

Quartz 1.55 

Canada Balsam 1.54' 



Crown Glass (mean) 1.53 

Alcohol 1.37 

Water 1.34 

Ice 1.31 

Air 1.000294 

— Olmstead's Philosophy. 



Fig. 6. 




i 


"^ 


i— -? / / 




>/ Q/~ J 













Qs/~ 



S' 



UKFIIACTION BY A MEDIUM HAVING PLANE PARALLEL SURFACES. 



(34) Substituting in article (31). 



, . sine a 
(1) i=— 



sine a 
(2) sine a =i sine a 1 
1 



Also (3) sine a 1 



-sine a 



l 



(2)x = (3)=(4) sine a = sine a 11 .*. the ray S and S 1 
are parallel, that is the incident and emergent rays by a refrac- 
tive medium having parallel plane surfaces will be parallel. 



14 



MICROSCOPY. 
Fig. 7. 



S* 




REFRACTION BY A MEDIUM BOUXDEI) BY INCLINED PLANES. 

(35) A transparent medium bounded by inclined planes 
is called a prism. The angle included by the planes is called 
the refracting angle and the planes are called deviating 
planes. 

(36) The total deviation by a prism is equal to the sum 
of the angles of incidence and emergence diminished by the 
refracting angle. 

(37) In fig. 7 let A B = the incident ray and G — 
the emergent ray. G D H will equal total deviation. 

(1) GDH = DBC + DCB. 

(2) i — i 1 = e — e 1 . 

(3) G D H = (i — i 1 ) + (e — e 1 ) = ( i + e) — 
(i 1 + e 1 ) 

Because of the perpendiculars at B and C, C K y and K 
B r are similar right angled triangles, therefore p = r. 

also (4) p = i 1 + e 1 
hence (5) i 1 + e 1 = r. 
Sub.in(3)=(6) G D H = i + e — r. Q. E. D. 



MICROSCOPY. 
Fig, 8. 



15 




TO FIND OPTIC CENTER OF CONVEX LENS. 

(37) The incident and emergent rays which enter and 
leave a lens at the points of contact of two parallel tangents 
will be parallel according to Article 3i. The point where 
such a ray cuts the axis of the lens is called the optic center. 
It may become necessary to produce the axis. 



In fig-. S, a and b are the points of contact of the parallel 
tangent planes. The radii C a and C 1 b being perpendicular 
to these planes are parallel to each other. 



Hence ( 1 1 Angles o and o 1 are equal. 
And (2) Angles at Pare equal. 

Therefore (3) Triangles C a P and C b P are similar. 

Represent C 1 b, one radius, by r 1 and Ca the other radius 
by r. Represent thickness of lens measured on the axis by t, 



16 



MICROSCOPY. 



and distance from optic center to surface by e. From 1, 2 
and 3 we get 

(4) C 1 P : C P : : C 1 b : C a. 

Sub. (5) r 1 — e : r — (t — e) : : r 1 : r. 

(6) r 1 r — r e = r 1 r — (r 1 t — r 1 e) = r 1 r — r 1 
t + r 1 e. 

(7) — r 1 e — re= — r 1 t. 

(8) e (r 1 + r) = r 1 t. 

Fig. 9. 




CONJUGATE FOCI. 

(38) Tbe relative distances of the conjugate foci can be 
determined when the refractive index and radii are known. 
Let x = refractive index and assume that the angles of inci- 
dence and refraction are so small that their ratios are the 
same as the ratios of their sines. 

Then (l)BGP:(=KGI):I6H::x:l. 

By div. (2) K G I— I G H : I G H : . x— 1 : 1. 

Substituting (3) K G H : I G H : : x— 1 : 1. 

(4) K H G : I H G : : x— 1 : 1. 

(3) + (4) =(5) KGH + KHG:IGH:: x— 1 : 1. 

But (6) K G H + K H G=B K F=K RF+KFE. 
And (7) I GH + IH G=P I C = I C G+I C 1 C. 
Therefore (8) K K F + K F E : I C C 1 + I C 1 C : : x— 1 . 1. 



MICROSCOPY. 17 

The angles at R, C, C 1 and F are as the reciprocal of the 
the distance from L., therefore substituting in (8) we have, — 

W RL + FL CL + C'L * 

To Find Principal Focus ; 

(39) In that case „ y would equal -^- and let the 
principal focus equal F then 9 in Art. 38 would equal : 

W a 1 " p ' C L C 1 L ' ' x ' co — °* 

Hence [2) -^i ^ T + ^j- : : x - 1 : 1. 
Formulae 9 and 2 may be applied to any form of lens. 

To Find the Power of Any Lens. 

(40) The reciprocal of the principal focal length of a 
lens is called its power. 

From 9 in Art. 38 we find, 

(1) WL + FT = ,x ~ 1} ( CTL + -Wl) 
And 2 in Art. 39 equals 

(2)-p = (x — 1) Qjj- + ^j-) ; therefore 

{ ' F RL T FL 

(4) F = p T — j — ,-, ."* = power of lens. 

Li Li -\- r L 

Fig. 10, 



(41) To find the power of a combination equivalent to 
a single lens : 

Let a ray parallel to the axis be incident at R and S T be 



18 MICROSCOPY. 

the emergent raj. Draw R C parallel to ST. AC will rep- 
resent the focal length of a single lens having the same devi- 
ation as the above combination. A X is the focal length of 

A. Let a represent the distance between the lenses. Then 
B X = A X — a. If we regard T as one of the foci then 
X must be the virtual conjugate of lens B corresponding to 
T. Let f equal focal length of A and f 1 equal focal length of 

B. Then, 



(l)rp 



1 1 1 



B T B X' 
But (2) B X = f — a. 

Ill 



Art. 40. 



f 1 


B T 


f - 


- a 


i 


1 


, l 




B T 


~~F 


1 f — 


a 


1 


f 1 


+ f — 


a 



Therefore (3) 

(i) 

(5) BT~ P(F— ^ 

From similar triangles A C R, B T S and X A R, X B 
S, we have, 

(6) (B T : A C : : B S : A K : : B X : A X. 
But A C equals F the focal distance of the combination. 
Therefore (7) B T : F : : B S : A R : : B X : A X. 
B T _ B X 

(8) ~F AX 

(9) B T x A X = F x B X. 

Sub. (10) ,■? 4- F x f = F x (f — a. i 

i ~\~ t — a 

f + f_ a f — a " 1 
(U) fMf-a) X ~T~ =T 
When the lenses are in contact a = o. 

(12) -y^-— ~f~ +-7T from which we get : 
K y r t i 

(42) The power of a combination of two lenses in con- 
tact is equal to the sum of their respective powers. 

The above formula can be applied to any number and 
form of lenses. 

Due attention must be paid to the signs of the powers. 



MICROSCOPY. 



19 



IMAGES. — (Z., imago, image.) 
(43) Lenses form a great variety of images. Their size 
and position depend on the kind of lens and position of the 
object. If in a convex lens the object is placed between the 
principal focus and the lens, the image will be virtual, erect and 
enlarged. If the object is further from the lens than the prin- 
cipal focus the image will be real, inverted and enlarged. 
All real images are inverted. 

In the compound microscope there are two kinds of im- 
ages formed, one real, the other virtual. 



be 
iZ 



yffi'MP 




W'^ 



20 MICROSCOPY. 

(4A) Fig. 11 shows the simplest form of the compound 
microscope. a is the object glass or objective. The object 
is placed a little beyond the principal focus, when a real, in- 
verted and enlarged image is formed at d, this real image is 
further magnified by the eye piece A. This second image 
is virtual and enlarged. The relative positions of the object- 
ive and eye piece change the magnifying power. It is neces- 
sary to form two ratios to find magnifying power of objective. 
The diameter of the object is to the diameter of the image as 
the distance of the object from the objective is to the distance 
of the image from the objective, that is : b T : d T 1 : : b x : d 
x. A similar proportion may be formed for the eye piece : 
ce:df : : A e : A f . The magnifying power of the object- 
ive times the magnifying power of the ocular gives full mag- 
nifying power. 

PRACTICAL PROBLEMS. 

(1) In a prism the angle of incidence is 30° 41*, the 
refracting angle is 25° 30\ What is the total deviating 

angle ? 

(2) Find conjugate focus of a convex lens whose 
radius is seven inches and whose refractive index is 1.6. One 
focus being 3 feet from optic center. 

(3) Find power of above lens. 

(4) Find principal focus of a convex crown lens whose 
radius is 12 in. 

Note. — Teacher should assign some twenty similar prob- 
lems. 

MICROSCOPES. 

Microscopes, as before stated, are of two kinds, simple 
and compound. There are at present only a few important 
forms of the first. These we will now consider. Theoretical- 
ly the spherical lens will give the highest amplyfying power, 
but it was soon found that as amplification increased, spheri- 
cal and chromatic aberration increased also ; hence it became 
impracticable to use the highest powers. These effects of ab- 



MICROSCOPY. 



21 



erration increase toward the periphery. In the Coddington 
lens which consists of a sphere of glass, this defect has been 
partially corrected by cutting a deep groove around the mar- 
gin and filling it up with some opaque material to cut off the 
distorted marginal rays. This lens focuses very near the ob- 
ject. Fig. 12 represents a section of the Coddington lens. 

Fig, 12. 



The Stanhope magnifiers consist of a double convex or a 
plano-convex lens. It is so ground that the plane or least 
convex surface is just in focus for the object. Good results 
are obtained from this lens but it is less convenient than some 
other fonn as the object must be fastened to the surface. 
Both the Coddington and Stanhope magnifiers are in use yet, 
but are rapidly making way for more convenient forms. 

Sir David Brewster was the real inventor of the Cod- 
dington lens It received its present name from a Mr. Carey 
who constructed one for Mr. Coddington and supposed he 
was the inventor. Fig. 13 shows a Stanhope lens. 



Fig. 13. 



Fig. 14. 

c 



Fig. 15. 




Wollaston and Frauenhofer made partially corrected 
doublets, that is two lenses in contact, one double convex of 



22 MICROSCOPY. 

crown, the other plano-concave of flint glass. John Brown- 
ing constructed achromatic triblets which were very useful as 
they focused at three times the distance that the Coddington 
lenses did and hence made it easy to examine opaque objects. 
Steinheil, a German optician, made similarly constructed 
lenses which he termed u aplanatische loupen" (aplanatic 
lenses) having a magnifying power of 5.5 to 24 diameters. 
Figs. 14 and 15 show a doublet and a triplet. 



COMPOUND MICROSCOPES. 

Before attempting to do anything in microscopy the stu- 
dent should have a thorough understanding of the mechani- 
cal construction of the compound microscope. Under the guid- 
ance of an instructor he should be shown the various parts 
and their modes of operation. Skill in microscopy is only to 
be obtained by diligent study and patient practice. Before 
commencing any investigation che student should lay aside all 
preconceived ideas and rely principally on his own observa- 
tions, for "things seen are not as things heard." It is not 
necessary that the beginner should have all the expensive ac- 
cessories belonging to a microscope. They are sometimes 
convenient and save time, but one having mechanical skill 
and ingenuity can make contrivances for himself that will 
answer the purpose very well. 

We will now consider the parts of the compound micro- 
scope and a few of the most important accessories. The first 
thing to be considered is the stand. The office of the stand 
is to hold the objectives and oculars in their respective posi- 
tions. 

Stands are built on two models, Jackson and Ross. In 
the Ross model the body is supported on a transverse arm, 
this is again supported on the summit of a racked stem which 
can be moved up and down by a wheel and pinion. The body 
itself is permanently fixed. In the Jackson model the body 
has the rack-work attatched to it and is supported for a great- 



MICROSCOPY. 23 

er part of its length on a solid base. Very few stands are 
now made on the Ross model because it is less firm and dur- 
able than the Jackson. The Ross stand leaves nothing to be 
desired if well made. But taking it all in all the Jackson is 
the best stand for either cheap or costly instruments. 

The base or foot is that portion of the stand upon which 
the other parts are supported. It should have three points of 
support, never more, because three points will always rest 
firmly no matter how uneven the surface may be. Some are 
of a triangular or horse shoe shape. The one having the 
three points of support is the best. 

The second part of the stand is the pillar. It is fastened 
to the foot and has upon its summit the joint or axis. There 
may be one or two pillars. They should always be firm and 
strongly made. 

The third part of the stand is the arm which is connected 
to the pillar by the axis and supports some of the principal 
parts of the instrument. 

The fourth part of the stand is the body which is the 
tube portion working upon the arm by means of a rack and 
pinion. It holds the objective, ocular and draw tube. The 
tube is generally made of brass. Some are nickle plated and 
all are black on the inside so as to prevent the reflection of 
light. The standard length of the tube is six inches. The 
lower end of the tube contains an extra piece called a nose- 
piece into which the "Society Screw" is cut. 

The "Society Screw" is so called because it was estab- 
lished by the Royal Microscopical society of London, They 
agreed that the threads on objectives should be cut of uniform 
size and the screws should have equal diameter. All objec- 
tive makers who have adopted the resolutions of the London 
society can interchange their objectives and use them with 
any stand. Never purchase an instrument that has not the 
"society screw." 



24 MICROSCOPY. 

OBJECTIVES. — (Z., ob, against, and jacere, to throw.) 

Before explaining the construction of objectives and 
oculars we shall first consider chromatic and spherical aberra- 
tion. 

By chromatic aberration (Gr., chroma, color; and L., 
abberans, to deviate) we mean a separation of the prismatic 
colors due to their difference in refrangibility. To produce a 
distinct image all the colors must be together, hence we al- 
ways have indistinctness accompanied with the separation 
of the colors. Different substances have different dispersive 
powers. This fact was discovered by Dolland, who thereby 
removed a great obstacle to the perfection of optical instru- 
ments. 

Below we give the dispersive powers of a few substances 
much used in optics : 

Plate Glass 032 

H 2 S 4 031 

C 2 H 6 O. 029 

Rock Crystal 026 

Blue Saphire 026 

Ca Fl 2 022 

— 01m stead. 

We will suppose that two prisms, one of crown and the 

other of flint be so ground that the refracting angle will 

separate the violet 5 1 from the red ray. In order to do this, 

the crown prism whose dispersive power is .030 must refract 

51 
the ray 2°19 1 , because = 2°19 1 . The flint prism whose 

dispersive power is .052 must refract the ray l^B 1 ; because 

= 1°36 1 . Place these prisms together base to edge. 

Then the crown glass will refract the beam downward 2°19 1 
and the flint glass will refract it upward l^O 1 . Now the dis- 
persive powers of the two prisms acting in opposite directions 
and with the same force (5 1 ) will just neutralize each other. 
The colors are therefore united and still the beam is refracted 
downward (2°19 1 ) — (l^ 1 ) = U\ 



Oil of Cassia .... .139 

Almond Oil 079 

Flint Glass 052 

H CI 043 

Diamond 038 

Crown Glass 036 



MICROSCOPY. 



25 



It can readily be seen how the same effect can be pro- 
duced by means of lenses. A convex lens of crown glass 
may produce a certain amount of dispersion ; this may be 
neutralized by a concave lens of flint according to the ex- 
planation given above. 

In practice it is found that when the violet and red rays 
are brought together, all intermediate points do not meet at 
exactly the same point, because the prismatic colors are not 
separated by like intervals. Opticians usually correct those 
rays which affect the eyesight most powerfully. 

SPHERICAL ABERRATION. 

Spherical aberration is due to the fact that the rays near 
the margin are more refracted than those toward the axis. 
The more nearly the lens approaches a sphere the greater will 
be the spherical aberration. In earlier times and at present 
in cheap lenses, this defect was corrected by means of a dia- 
phragm which would cut off the distorted marginal rays. 
Now the correction is made by using lenses of an elipsoidal 
form or by using wider back lenses. 

Fig. 16. 





In fig. 16 a, represents the appearance of a ruled plate as 
seen through an aplanatic lens, that is one free from spherical 
aberration ; b, represents the same plate as seen through a non- 
corrected convex lens, and c, as seen through a noncorrected 
concave lens. 
The objective is that part of the microscope which forms 



26 MICROSCOPY. 

the real image and is screwed into the lower end of the tube. 
Objectives consist of a series of lenses ground to suitable 
curvatures depending upon the desired magnifying power and 
angular aperture. These lenses are held in place by the 
mount. Objectives are generally spoken of in terms of their 
amplification. The standard of comparison being the magni- 
fying power of a single lens having the given focal length. 
For example, a one-fourth inch objective does not focus one- 
fourth inch from the object but has the same magnifying 
power that a single lens would have with a focal length of 
one-fourth inch. The one-fourth inch may focus much nearer 
than one-fourth of an inch, that depending upon the angular 
aperture. The wider the angle the nearer it will focus to the 
object. Objectives are spoken of as high and low powers. 
All below the one-fourth inch are called low powers, the 
fourth inch and above are called high powers. 

By aperture we mean the opening made by the extreme 
marginal rays meeting at the focus. Much controversy exist- 
ed in regard to aperture. Some claiming the high angles 
were best and others favored low angles. Nearly all opticians 
have come to the conclusion that it is always best to have the 
highest possible angle. Aperture is either given in degrees 
or its numerical value. Air angle may range from 10° to 175° 
Some opticians have made lenses claiming to be " infinitely 
near 180°." This seems almost impossible as some allow- 
ance must be made for the thickness of the cover glass. The 
student will readily understand that the wider the angle the 
more rays will be utilized in forming the image, and hence 
better definition and truer image. It is also plain that high 
angles will focus very near the object and therefore allow but 
little working distance and room for vertical illumination. 
All objectives having a higher aperture than 175° must be 
used as immersion objectives, that is some transparent liquid 
must be placed between the object and objective having a 
higher refractive index than air as water, oil, or balsam. 
These liquids increase refraction and allow the objective to 



MICROSCOPY. 27 

focus farther from the object. The beginner should not get 
the high angle objectives as they require delicate manipulation 
and skill to do successful work. 

Instead of giving a separate angular value for each of 
the various immersion fluids, a comparative numerical value is 
given in which the air angle is considered to be the standard. 
The numerical aperture is found by multiplying the sine 
(natural) of the semi-air angle by the refractive index of the 
immersion fluid used. 

Objectives are either made of a double or trible sys- 
tem of lenses. Low powers and angles may be made of 
a single system. Most triblets have a single front lens, a 
double middle and a trible back lens. " Wenham's Formula" 
is a trible combination having a flint concave of a trible mid- 
dle to correct the aberration of the single anterior and pos- 
terior crown lenses. 

There are also separable and adjustable objectives in the 
market. The student is advised not to buy or use them. 



EYEPIECES OR OCULARS, (L., oculus, eye.) 

The eye piece slides into the upper end of the draw tube 
and forms the virtual image. There are three kinds of ocu- 
lars in use, the Huyghenian, solid and orthoscopic. The 
most common variety is the Huyghenian so named after its 
inventor who first used it with his telescope. It consists of a 
small upper lens called the eye lens and a larger lower lens 
called the field lens and diaphragm between, not midway, but 
nearer the field lens in the ratio of 1 : 3. They are some- 
times called negative eye pieces because the convexity is 
turned from the eye. High powers are termed "deep" and 
low powers "shallow," these terms refer to the curvature of 
the lenses. Solid eye pieces were the invention of Mr. Tolles. 
They are called solid because they consist of one solid piece 
of glass on the ends of which the proper curvatures arc 
ground. A groove is cut into the glass at a proper distance 



28 MICROSCOPY. 

between the two ends and filled up with some opaque sub- 
stance to answer for a diaphragm. They are used principally 
with high powers. The orthoscopic ocular consists of a trible 
eye lens and a single field lens with no diaphragm. It is well 
adapted for micrometer work. 

Eye pieces are not made of the same size, hence the ocu- 
lars of different makers can not be used with other micro- 
scopes. 

Oculars are generally named A, B, C, D etc., but the D 
of one maker will not have the same amplification as the D 
of another maker. American manufacturers name theirs like 
the objectives, two inches, one inch, one-half inch, etc., ac- 
cording to their magnifying power. 

In selecting good objectives the following qualities are to 
be considered : 

(1) Working distance. 

(2) Definition. 

(3) Freedom from distortion. 

(4) Penetrating power. 

(5) Resolving power. 

Working distance. — By working distance is meant the 
distance between the object and lens when in focus. It de- 
pends upon the aperture and magnifying power. Great work- 
ing distance is valuable for dissecting purposes and the ex- 
amination of opaque objects. But when an object has been 
prepared and mounted for transmitted light there is no need 
for more working distance than will admit of the use of the 
cover glass. 

Definition. — This is the most important property of ob- 
jectives and should always be taken into consideration. It 
depends on the absence of both forms of • aberration. An 
objective that is achromatic and aplanatic will have perfect 
definition. The image by such an objective will appear dis- 
tinct to the very edge. There should be no discolorization or 



MICROSCOPY. 29 

distortion. Be sure to test an objective for definition before 
buying. 

Freedom from distortion. — This depends on the correc- 
tion for spherical aberration. Those whose field of vision 
should be well defined under one focusing, margin as well as 
center. As a test object the "Nobert band plate" is very 
much used. It consists of a plate of glass with lines ruled 
upon it ranging from 1,000 to 112,000 to the inch. The lines 
should appear parallel and straight. 

Penetrating power. — It is that property by virtue of 
which several planes of an object may be seen at one focus- 
ing. It depends on two things, accommodation depth of the 
eye and depth of focus. These depend on the aperture and 
amplification. The higher the power and aperture the less 
penetration. For some reason the accomodating depth of the 
eye does not decrease as rapidly as the depth of focus. 

Great penetration is useful in examination of opaque ob- 
jects and in the examination of transparent objects that can 
not be cut thin. 

Resolving power. — This is another very important prop- 
erty and depends always wholly upon large aperture com- 
bined of course with correction for sphericity and chromatism. 
As a test the "Nobert test plates" are used having lines 
ruled on them ranging from 10,000 to 200,000 to the inch. 
Mr. Mceller has made what he calls a " test platte" (test 
plate) upon which he has mounted twenty diatoms having 
striatums ranging from 3,000 to 92,000 to the inch. The 
better the resolving power the more of these lines can be seen 
to every linear inch. 

The draw tube is supplied with most monocular micro- 
scopes. The draw tube slides into the tube, at the upper end 
is a milled collar which acts as a stop. The eyepiece is fitted 
into the upper end and by this means the draw tube becomes 
an aid in increasing the magnifying power. Some of these 



30 MICROSCOPY. 

tubes are plain and others are divided into inches and parts 
so that results may be noted. 

Coarse adjustment is a contrivance for moving the body 
back and forth quickly. It is done by means of a rack and 
pinion, and sometimes by merely sliding the tube in an outer 
sheath. The rack and pinion is far more preferable. 

The fine adjustment is used after an approximate focus 
has been obtained by the coarse adjustment. It is attained 
by a fine thread acting upon the body directly or by means of 
levers. 

Both adjustments should be very sensitive. They should 
have true fittings and gearings, anything to the contrary gives 
evidence of poor workmanship. 

The stage is that part upon which the object is placed for 
examination. It is attached to the arm and may be either 
fixed or revolving on an axis. The stage should be made very 
hard and smooth. Glass stages are the best. 

The mirror is placed below the stage on the sliding and 
swinging mirror bar so that it may be turned in any direction. 
Mirrors are generally either plane or concave. Most all mir- 
rors have two surfaces one plane the other curved. Experi- 
ence and a knowledge of optics will give the best informa- 
tion as to their proper use. 

The diaphragm is a contrivance with which to regulate 
the admission of light. They are of two kinds — wheel and 
iris diaphragms. The wheel diaphragm consists of a disk 
with holes of different sizes. The iris diaphragm consists of 
a number of movable shutters. These are made to open and 
close, similar to the human iris, by means of a thumb screw. 
Diaphragms are either attached to the stage or sub-stage. 
The proper position for the opening is as near the slide as 
possible. 

The sub-stage is a ring below the stage to receive various 



MICROSCOPY. 31 

accessories. It is generally provided with an adjustment to 
regulate its distance from the object. 

The bull's eve condensor is a double or plano-convex 
lens mounted on a stand for the purpose of concentrating 
light upon an opaque object. Its use and manipulation de- 
pends upon its construction. 

The sub-stage condensor is attached to the sub-stage. It 
consists of a combination of lenses and is corrected for both 
forms of aberration. It can only be used with satisfaction 
by advanced students. 

Double and trible nose pieces are useful when it is desired 
to quickly change objectives. They may be made to hold 
objectives of different powers which can be swung in and out 
of focus whenever desirable. Those holding three, four or 
more objectives are generally too clumsy. 

Microscope Tables .—When two or more microscopists are 
at work at the same time it is convenient to have a revolving 
table as it saves a great deal of rising to change places in 
observing. The table should have three supports and should 
be well made. One that creaks and is loose at every joint is 
worse than useless. The larger the table the more can con- 
veniently work at the same time. 

Microscope Lamps. — The best time to work is day time, 
using the light from a white cloud on a sunny day. Never 
use direct soulight ; it is too bright. When it becomes neces- 
sary to D86 artificial light an ordinary student lamp can be 
used. To protect the eyes all superfluous light may be cut 
off by a shade. To get the most intense light turn the edge 
toward the object, but if quantity of light is required rather 
than intensity the flat side may be used. The student should 
be careful not to use too much light as it sooner or later ruins 
the eye sight. Lamp light gives a very objectionable yellow 



32 MICROSCOPY. 

tint to objects ; this may be corrected by colored glass. 
Blue glass very effectively corrects this defect. The blue 
glass used by chemists does very well. 

Camera Lucida, (L., camera, an arched roof; and lucida, 
bright.) — The student should always delineate objects under 
examination. The image is thereby more firmly fixed in his 
mind, besides it teaches him to observe more closely. He 
will be surprised to find that he observes things which he 
would not have noticed otherwise. The camera lucida and 
neutral tint reflector are contrivances used with the micro- 
scope in drawing images of objects under examination. The 
student of average ability can construct the neutral tint re- 
flector for himself. Take an ordinary cover glass, incline it 
45° to the eye lens of the ocular, so that the center of cover 
glass and center of eye piece will coincide, fasten it in its 
place by some contrivance. Now incline the tube of the mi- 
croscope till it is at right angles to the pillar. The cover 
glass will refract the image at right angles. The eye looking 
down through the center of the cover glass will see the image 
projected on a paper placed below on the table. The posi- 
tion of the light and mirror must be changed to produce the 
proper illumination. Be careful not to have too much light 
where you are going to draw. A prime object in drawing is 
to produce exact representations. The student should use 
paper ruled into squares. Place a cover glass ruled in squares 
on the diaphragm of the ocular ; this projects the image of 
the squares with the image of the object. By this means very 
exact work can be done. Amplifications and reductions can 
be made at will. Cut off most of the light from the paper on 
which the image is projected, so that it will appear in clearer 
outlines. Get a good, sharp lead pencil and trace the outline 
of the image on the ruled paper. It is well to use a tinted 
cover glass, as it gives a better defined image. The student 
will be surprised to find what he can accomplish by this sim- 
ple means. 

The camera lucida consists of a prism, and is used in the 
same manner as the tint reflector. 



MICROSCOPY. 33 

Miccometer, (Gr., mikros, small ; and metron, measure). 
This is a contrivance for measuring all microscopical objects. 
In the present age of progress the metric system is coming 
more and more into use ; hence it is best to get those mi- 
crometers ruled occording to that system. They are gener- 
ally ruled to millimeters, tenths and hundredths. Our best 
scientific works give all measurements in that system. The 
stage micrometer is placed on the stage of the microscope, 
just below the object slide. It can only be used directly with 
low powers, as the object and micrometer must be in focus at 
the same time. With high powers another method may be 
employed. Make a drawing of the object by means of the 
camera lucida. Now replace the object by the micrometer, 
and draw its markings over the previous sketch. Simple 
inspection will show the magnitude of the object. 

Eye-piece micrometers slide into the ocular just over the 
diaphragm. These micrometers must be corrected for differ- 
ent powers. The actual experience, directed by a teacher, 
is best here. 

Numerous other accessories could be mentioned, but the 
beginner is advised to purchase only those that are absolutely 
necessary, as they are generally very costly and are too much 
of a strain on the purse. The beginner will also soon find, to 
his sorrow, that he can not use them. Never buy anything 
because it is cheap ; rather because it is good. The person 
who buys a microscope, or anything else, because it is cheap 
is the loser in every case. Some advice on the purchase of a 
microscope might be in order: 

1. Make up your mind as to what you want before you 
make up your mind to buy. 

2. Select a good, strong, Jackson stand in which all the 
gearings work smoothly. It should always admit of the use 
of the more important accessories. 

3. Select good objectives, and test them before buying. 
This is of special importance. 



34 MICROSCOPY. 

4. Select good oculars and test them. 

5. Deal only with reliable firms. 

6. Take good care of your instrument. Do not let 
every one handle it, especially those who know nothing 
about microscopy. 

A little advice on keeping a microscope might be in 
order : 

When through using the microscope seperate the various 
parts as much as is necessary, and wipe them perfectly clean 
and dry with a silk handkerchief or a piece of chamois skin. 
Rub up and down, lengthwise, with a light, brisk movement. 
When through wiping no finger marks should be seen any 
where. Place the various parts in their proper places in the 
microscope case. Do not throw half finished mounts, slides, 
cover glasses, botanical specimens, etc., helter skelter into 
the case. The microscope case was made for the microscope 
only. After being certain that everything is in its proper 
place, lock the case and put the key in your pocket or some 
other place where you know it can be found when wanted. 
Keep the microscope, or any other scientific instrument, in a 
dry place, away from chemicals. 



CHAPTER II. 

BIOLOGY. 



Biology, (Gr. bios, life ; and logos, discourse.) or natural 
history, is the science which treats of the organic world in its 
various forms and relations. It includes the entire fields of 
zoology and botany. The two are inseparably connected. 
Scientists have so far been unable to draw the dividing line. 

In all scientific investigations a systematic classification 
and arrangement is necessary, not so much for the original 
researcher, but that it can be properly presented and under- 
stood by those who follow in the field of investigation. Biol- 
ogy, as the word signifies, is a life discourse, and treats of the 
composition and corelation of organic bodies ; it is, therefore, 
distinct from mineralogy, which treats of minerals, or inor- 
ganic substances. For convenience sake biology is divided 
into zoology and botany. 

Zoology is the science which treats of animated nature. 
It can first be divided into structural zoology, which treats of 
the organization of animals. Structural zoology is divided 
into anatomy, which treats of the constitution and formation 
of animal bodies ; and physiology, which treats of the func- 
tions of the organs of organized bodies in a healthy state. 
Pathology treats of functions in an abnormal state. Anatomy 
separates first into descriptive anatomy and histology. This 
divides again into skeletology, which comprises osteology and 
syndesmology ; and sarcology, which comprises myology, 
neurology, angiology, adenology, splanchnology, and derma- 
tology. Secondly, anatomy separates into embryology, which 
is the doctrine of embryonic development ; and, thirdly, 
morphology, which treats of the anatomical conformation of 



36 BIOLOGY. 

parts. Horuological anatomy treats of the relation of differ- 
ent parts in the same individual. Comparative anatomy 
treats of the relation of like parts in different individuals. 
Philosophical anatomy treats of or inquires into the mode or 
model upon which the animal body is formed. ' Morbid anat- 
omy treats of organic structure in a diseased state. Historical 
zoology treats of the successive appearance and disappear- 
ance of animals in the various ages. It is divided into geo- 
logical zoology, which treats of animals now extinct, and 
recent zoology, which treats of animals now living. Theoret- 
ical zoology attempts to explain the possible origin of life and 
species. Space will not permit the giving of a complete out- 
line of biology. 

The actions of living matter are called its functions. 
These functions, though very numerous, may be resolved into 
three kinds — (1) functions which effect the material composi- 
tion of the body, and determine its mass, which is the balance 
of the process of waste on the one hand, and assimilation on 
the other ; (2) the functions that subserve the process of 
regeneration, which is nothing more nor less than a detach- 
ment of a part having the power to develope into an inde- 
pendent whole ; (3) functions by virtue of which one organ 
has the power to exert an influence upon other organs in the 
same body, and thus become a mode of molar motion. The 
first may be termed sustentive, the second generative, and 
the third correlative functions. The most complex body is 
merely an aggregate of cells. 

Among the more simple forms of animal life known to 
biologists is the amoeba, closely resembling a white blood 
corpuscle, and consisting almost wholly of an undifferen- 
tiated mass of protoplasm. Generally there are present 
one or more nuclei, although these may be absent. This 
simple organic structure possesses all the most important 
fundamental vital properties found in the most complex 
body known. (1) It is contractile. It can produce within 
itself a change in form and position by what is so well 



BIOLOGY. 37 

known as the "amoeboid movement. (2) It is irritable, or 
automatic. When it comes in contact with a foreign body 
motion is the result. This is not passive but active motion. 
In fact, the amoeba is rarely at rest. (3) It is receptive and 
assimilative. It has the power to take up and assimilate por- 
tions of certain substances for food. (4) It is metabolic and 
secretory. That is, the protoplasm undergoes a continual 
change. The protoplasm now existing breaks" up and is 
removed, w T hile a new protoplasm is formed from the food 
taken up. (5) It is respiratory. It takes in oxygen, which is 
required in the oxidation of food, and gives out carbon diox- 
ide, which is the result of oxidatiow. (6) It is reproductive. 
The individual amoeba represents a unit ; after a time this 
unit divides into two separate units capable of again subdi- 
viding. 

Many eminent biologists have attempted to explain the 
possible origin of life and species. Some theories have 
been advanced, but none of them have yet been able to stand 
alone. They fall to the ground as soon as their promulgat- 
ors cease to support them. We might say that life is a series 
of changes, both in structure and composition, wrought by 
some intangible, incomprehensible force, such changes always 
taking place without destroying the identity of the individual. 
The most plausible theory, or rather, hypothesis, in regard to 
the origin and development of species is that of evolution, 
brought to its present perfection by Charles Darwin. He 
defines it as a changing from the homogeneous to the hetero- 
geneous, from the general to the special, from the simple to 
the complex. It is, essentially, a process of differentiation, a 
a method of progress from generalized types to those more 
special and complex — a changing from a lower to a higher 
individuality. 

This hypothesis is by no means recent. It existed 
among tjie ancient philosophers. An old cosinologieal 
myth was that, at first, there existed ;i chaotic mass or 
mundane egg, from which all things successively emerged. 



38 BIOLOGY. 

Thales taught that in the beginning every thing was in a fluid 
state, from which some great, self-existing force formed all 
things. Anaxagaros taught that, at first, all consisted of 
atoms, infinitely numerous and eternal, among which order 
and arrangement was produced by a self-existing, intelligent 
power or god. This was opposed by Democritus and Epi- 
curus, who taught that chance, and not God, wrought, in infi- 
nite time, out of numberless atoms, all existing things. 

No student in biology can afford to jump at conclusions. 
He must lay aside all preconceived ideas and notions, must 
allow nothing to come in the way of sound judgment. Fore- 
most among all the foundation npon which evidential knowl- 
edge is to be placed, must stand every test brought to bear 
against it ; for, if the foundation is rotten, the superstructure 
will fall to the ground, no matter how well it may be planned. 

Not until the perfection of the compound microscope was 
it possible to make any real progress in biology. By means 
of it we have discovered the ultimate constituents of organ- 
ized bodies, the cells, and have been enabled to study the 
lower forms of the organic world, such as the algae and bac- 
teria. In comparatively recent time eminent biologists 
believed that cells and minute organisms could originate cle 
novo; but it has been conclusively shown that every living 
cell sprang from a pre-existing cell. Of course, leaving out 
of consideration the question as to where the original cell 
or ovum came from. 

The animal and vegetable world is composed principally 
of four elements: oxygen, hydrogen, nitrogen and carbon. 
The first three are gases; the last, carbon, is a solid. Carbon 
has the property of interchanging its combining power, which 
accounts for the many carbon compounds found in nature. 
The predominance of gaseous elements in the organic world 
is supposed to account for its high degree of molecular mobil- 
ity, and, according to Herbert Spencer, "that comparative 



BIOLOGY. 39 

readiness displayed by organic matter to undergo those 
changes in the arrangement of parts which we call develop- 
ment, and those transformations of motion which we call 
functions." The primary form into which the four elements 
enter is the semi-fluid substance called protoplasm, which is 
almost the sole constituent of the lower forms of animal life. 
Combined in different forms, these elements enter into all the 
compounds found in the animal and vegetable world. 

In the entire organic world nothing is at rest. There is 
a continual change and interchange of cells and cell sub- 
stance ; this change always tends toward a higher individual- 
ity. The time will come when the present genera and species 
will make way for higher organizations, as much higher than 
we are as we are higher than those who lived before the great 
glacial epoch. We can only affirm that in judging the future 
by the past. We have noted the steady progress of develop- 
ment, and we have no cause to think that we are now at the 
acme of all progressive development. 

As has been stated, the biologist has so far been unable 
to draw the dividing line between the animal and vegetable 
kingdoms. It is very probable that the lowest forms of ani- 
mal and vegetable life existed together. No doubt, the high- 
est developed plant, as well as man, sprang from the same 
primordial mass of protoplasm. Beginning with Haeck- 
el's moners, the two great kingdoms begin to separate, each 
in its line, rising to a higher degree of development. These 
two kingdoms developed because one was the supporter of 
the other. What one discards the other uses. No third or 
fourth organic kingdom developed, because it was not needed. 
In the future nature may be in demand of entirely different 
organisms than we now find. 

The beginner is advised not to study unknown forms of 
life till he understands those which have been described. 



40 



BIOLOGY. 



Below is given an outlined differentiation between the 
lower typical forms of vegetable and animal life : 



UNICELULAR PLANTS AND ANIMALS. 



ANIMALS. 

I 1 Composition. 

I 2 Protoplasm. 
2 1 Parts. 

I 2 Cell Wall. 

I 3 Albumen. 
2 2 Cell Contents. 

I 3 Nitrogenous Substan- 
2 3 Nucleus. [ces. 

3 1 Assimilation. 
I 2 Endosmosis. 
I 3 Water. 

2 3 Nitrogenous Substan- 
1* Albumen. [ces. 

2 1 Gelatine. 
2 2 Exosmosis. 

I 3 Carbon Dioxide. 
4 1 Reproduction. 
I 2 Division. 
2 2 Budding. 
5 1 Form. 

I 2 Irregular. 
6 1 Size. 

I 2 Microscopical. 
7 1 Motion. 

I 2 Generally in motion. 

In the animal kingdom, the 
Paramecium may be taken as a 
typical example for examination, 
and in vegetable kingdom some 
of the numerous forms of des- 
midia.. 



PLANTS. 

I 1 Composition. 
I 2 Protoplasm. 
2 2 Starch. 
3 2 Chlorophyll. 
2 1 Parts. 

i 2 Cell Wall. 

I 3 Cellulose. 
2 2 Cell Contents. 

I 3 Xilrogenous substan- 
2 3 Starch. [ces. 

3 3 Chlorophyll. 
-i 3 Xucleus. 
3 1 Assimilation. 

1 2 Endosmosis. 
i 3 Water. 

2 3 Carbon Dioxide. 
3 3 Ammonia. 
2 2 Exosmosis. 

1 3 Oxygen. 

i 1 Reproduction. 

I 2 Division. 

2 2 Spore Formation. 
5 1 Form. 

I 2 Spherical. 

2 2 Oval. 

3 2 Oblong. 

4 2 Cylindrical. 

5 2 Wedge-shaped. 

6 2 Linear. 
6 1 Size. 

I 2 Microscopical. 
7 1 Motion. 

I 2 Generally motionless. 



BIOLOGY. 



41 



Before entering upon any kind of work see that you are 
prepared and supplied with the necessary material for a be- 
ginner in biology. Some of the reagents can be omitted till 
they are absolutely necessary. 



MATERIAL FOE A BEGINNER. 



I 1 Microscopes. 

I 2 Compound Microscope. 
i 3 Accessories. 
V Objectives. 
I 5 One inch. 
2 5 One-fourth inch. 
2* Oculars. 

I 5 A or one inch. 
2 5 B or J inch. 
3 4 Bull's eye condensor 
4* Neutral tint reflector 
5 4 Camera Lucida. 
6 4 Micrometers. 
I 5 Stage. 
2 2 Dissecting Microscope. 
3 2 Simple Microscope. 
I 3 Coddington Lens. 
2 3 Stanhope Magnifiers. 
I 4 Doublets. 
2 4 Triblets. 
3* Achromatic. 
2 1 Dissecting case. 
I 2 Dissecting knives. 
2 2 Scissors. 
3 2 Forceps. 
I 3 Straight. 
2 3 Curved. 
4 2 Blow pipe. 
5 2 Camel's hair pencil. 
6 2 Dissecting needles. 
3 1 Microtome. 
4 1 Turn table. 
5 1 Slide Ceftterer. 
6 1 Pipette. 
7 1 Alcohol lamp. 



8 1 Glass slides. 
I 2 Smooth edge. 
2 2 Kough edge. 
9 1 Cover glasses. 

I 2 Various sizes. 
10 1 Labels. 
II 1 Slide boxes. 
12 1 Pencil drawing outfit. 
13 1 Reagents. (See recipes.) 
I 2 Hardening agents. 

I 3 Alcohol. [solution. 

2 3 Bichloride of mercury 

3 3 Tannin solution. 

4 3 Chromic acid. [sium. 

5 3 Bichromate of potas- 

6 3 Osmic acid. 
2 2 Softening agents. 

I 3 Acetic acid. 

2 3 Glycerine. 

3 3 Potash. 

4 3 Soda. 

5 3 Ammonia. 

6 8 Caustic soda. 

T 3 Nitric acid. 
3 2 Dehydrating agents. 

I 3 Phosphoric acid. 

2 3 Potassium carbonate. 

3 8 Calcium Chloride. 

4 s Beat. 
4 2 Bleaching agents. 

I 3 Chlorinated soda. 

2 s Chloride of lime. 

3 a ( lilorate of potassium. 

4 5 Bichromate of potas- 

5 3 Nitric acid. [sium. 



42 





BIOLOGY. 


6 3 Turpentine. 


6 2 Staining fluids. 


7 3 Chlorine. 


I 3 Carmine. 


5 2 Solvents. 


2 3 Haemotoxylin. 


I 3 Acids. 


7 2 Mounting mediums 


1 4 II 2 S 4 . 


l 3 Balsam. 


2 4 H N 3 . 


2 3 Glycerine. 


3* H CI. 


3 3 Water. 


¥ C, H 4 2 . 


I 3 Dammar. 


2 3 Alcohol. 


5 3 Mastic. 


3 3 Benzol. 


8 2 Finishing agents. 


4 3 Benzine. 


I 3 Oxide of zinc. 


5 3 Oil of Cloves. 


2 3 Carmine. 


6 3 Oil of Cajeput. 


3 3 Ultramarine. 


7 3 Chloroform. 


4 3 Lamp black. 


8 3 Ether. 


5 3 Verdigris. 


9 3 Petroleum. 


6 3 Chrome yellow. 



10 3 Water. 

Before one can do satisfactory work with the various 
reagents their actions upon different tissues must be under- 
stood. 

Among the hardening agents alcohol is the best and most 
used. It absorbs moisture very readily without destroying 
the fresh appearance of the tissue. It must be remembered 
that it dissolves gums and resins used in microscopical work. 
Bichloride of mercury is a very efficient preparatory harden- 
ing agent. It is supposed to act by forming insoluble albu- 
minoid compounds. It must be borne in mind that it is a pow- 
erful poison. Tannin is used for gelatinous substances. It is 
used to inject blood vessels to prevent the passage of color- 
ing matter through them. Weak solution of chromic acid 
combined with the bichromate of potassium is a good harden- 
ing agent for nervous tissues. Osmic acid in 1 per cent, so- 
lution is much used for protoplasmic substances. It is very 
poisonous. 

Softening Agents. — Acetic acid diluted with about four 
times its amount of water is much used. It renders tissues 
quite transparent. It dissolves phosphate and carbonate of 
lime. It can be combined with glycerine as a preservative 
fluid. Glycerine is probably most used. It prevents the dry- 



BIOLOGY. 43 

ing up of tissues. The alkalies all have a similar action upon 
most tissues. They are much used with vegetable tissues. 
Nitric acid is sometimes used as a softening agent. It must 
be borne in mind that it combines with metals of which the 
instruments, etc., are made. 

Dehydrating Agents. — These might have been given 
with the hardening agents as water absorbers are also harden- 
ing agents. Among the most important are anhydrous, phos - 
phoric acid, and concentrated sulphuric acid. The tissues are 
not placed in contact with then but in a separate place under 
a bell jar or some other air tight vessel. Potassium carbon- 
ate and calcium chloride are used in a similar manner. Dry 
heat is much used for different purposes, such as drying 
specimens for mounting and driving air bubbles from under 
cover glasses. 

Bleaching Agents. — Chlorinated soda and chloride of 
lime are much used in bleaching vegetable tissues, also chlor- 
ine. How to generate chlorine will be explained in another 
chapter. Always eliminate all traces of these reagents after 
the tissue is sufficiently bleached. This may be done by 
means of a solution of sulphite of soda, 15 grains to the 
ounce of water. Turpentine is used to remove the intensity 
of color from insect skeleton. Turpentine dissolves many of 
the varnishes and finishing agents used in mounting. 

Solvents. — The strongest solvents are the acids. A 
knowledge of chemistry will indicate when and where to use 
them. 

'The alkalies will dissolve oils and fat, forming a soap. 
Alcohol dissolves resinous substances. Benzol and benzine 
dissolve iodine, fat, gum, resins, rubber, etc. Turpentine, 
ether and chloroform are good solvents for fats and most 
resins. Water is the best universal solvent. Plenty of it 
should be used. The object of solvents is to remove foreign 
matter. Cleanliness is very desirable in microscopical work. 



44 BIOLOGY. 

Staining Fluids. — Carmine is best adapted for animal 
tissue while logwood is best for vegetable tissue. It is best 
to buy the fluids ready prepared. All dealers in micro- 
scopical instruments keep them. There are many other stain- 
ing fluids, but those two mentioned are the only ones neces- 
sary for the beginner. 

Mounting Mediums. — Pure Canada balsam is the best 
and most used. Dammar and mastic are also much used. 
Care is necessary in using glycerine. Water is only used for 
temporary mounts. , 

Finishing Agents. — Oxide of zinc is used to protect the 
edges of the cover glass. 

Carmine, ultramarine, lamp black, virdigris, etc., are 
used with some vehicle in making colored rings. (See 
receipes.) 

STARCH. (C 6 H I0 O 5 .) 

The examination cf starches and pollen is introduced 
here because they are easily obtained and will enable the 
beginner to become somewhat accustomed to the manipula- 
tion of the microscope, at the same time affording useful in- 
formation. 

Starch is one of the most important carbohydrates. It 
is very abundantly diffused throughout the vegetable king- 
dom. There is no plant in which it cannot be found during 
some stage of its existence. When purified it is a white, 
glistening powder which gives rise to a crackling sensation 
when rubbed between between the fingers. It consists of 
firm, minute granules, varying in size and shape. Each 
granule consists of a series of layers deposed upon each other 
causing the appearance of concentric markings. These 
markings are arranged around a point which is generally ec- 
centric in position called the hilum. The appearance of the 
concentric rin^s are due to the fact that the various layers are 



BIOLOGY. 45 

alternately harder and softer in comparison with each other 
which produces a difference in refractive power and hence 
the striations. 

Make temporary mounts and examine first with low 
power and then with the J-inch objective. 

Starches. — Laboratory Work. 
I 1 Potato starch. 
I 2 Hilum. 

2 2 Concentric rings. 
3 2 Shape. 

I 3 Irregular pear shaped. 
4 2 Size. 

I 3 From 2.5 to 62.5 m. m. m. in diameter. 
2 3 Comparative sive. 
5 2 Admit a drop of solution of iodine under cover glass. 
I 3 Note result and explain. 
2 1 Wheat starch. 
I 2 Hilum. 

I 3 Round or transverse. 
2 2 Concentric rings not distinct. 
3 2 Shape. 

I s Disc like, flattened. 
4 2 Size. 

I 3 2.5 to 35. m. m. m. in diameter. 
2 3 Comparative size. 
5 2 Admit a drop of solution of iodine. 
I 3 Note result. 
3 1 Oat starch. (See l 1 and 2 1 ). 
4 1 Corn Starch. (See l 1 and 2 1 ). 

(a) Boil some starch with diluted sulphuric acid (H 2 S 4 ). 
This process will convert it into a substance having the same 
chemical composition as starch but turns the plane of polar- 
ization to the right, hence it is called dextrine. (L., dextra, 
right, to the right.) By continuing the boiling dextrine is con- 
verted into sugar. 



46 BIOLOGY. 

(b) Carefully heat some starch in about 120 parts of 
water. The cellulose, which is insoluble, will settle to the 
bottom as a turbid deposit while the granulose form a per- 
fectly olear solution. 

(c) Iodine test for starch. 

(1) Heat some starch solution, add solution of iodine, 
no visible actions takes place. Allow it to cool and note re- 
sults. 

(2) Iodine must be in a free state. Solutions of iodine 
salts will not do. 

(3) The presence of a third organic substance will 
generally interfere with the test. 



POLLEN.— (L., pollen,, a fine flour.) 

Pollen is that part of the flower which develops the ger- 
minating power of the ovule. 

The student is supposed to be sufficiently acquainted with 
botany to understand the growth and development of plants. 

The stamens are simply modified leaves. The filament 
represents the stem of the leaf, while the anther represents 
the blade or leaf proper. The epidermis of the anthers is 
very much like that of the leaves only that it contains no 
stomata and generally no chlorophyll. The anthers or spore 
cases have a homogeneous parenchyma whose cells are close- 
ly crowded. After a time new cells develop within the case 
and rapidly multiply. These form the pollen. The sun's 
heat causes the pollen case to break open when the pollen 
escapes as a very fine powder and falls upon the stigma. 

We shall now describe a pollen grain more closely. It 
is simply a cell consisting of a cell wall and cell contents. 
The external cell wall or extine is what gives the pollen its 
form and color. All the many beautiful markings of the 
pollen which are always constant in the same species, are 
due to the extine. Hence from the examination of the pollen 



BIOLOGY. 47 

we may name the flower to which it belongs. The extine is 
formed out of a secretion from the internal coat or intine 
which directly envelops the viscid, protoplasmic, fertilizing 
fluid. 

The manner in which the pollen reaches the ovule is very 
interesting. It is well known that the stigma is continually 
covered with moisture. When the anther bursts open the 
comparatively dry pollen grain falls upon the stigma and 
is retained there by the thin viscid fluid. Osmosis takes 
place ; the more thin fluid of the stigma passes into the pol- 
len and also causes the hard, brittle extine to burst open at 
the surface which is in contact with the stigma. This allows 
the extensible intine to protrude. Osmotic action contiuues 
between the pollen and those cells of the stigma which are in 
immediate proximity. On account of the greater viscidity of 
the pollen fluid it gains more by endosmosis than it loses by 
exosmosis. This causes the stigma cells to shrink and create 
a space for the passage of the extended pollen membrane 
which we will now call the pollen tube. The reason that the 
intine does not simply expand on the surface of the stigma is 
because of the weight and resistance offered by the hard 
extine, and some directive influence not mentioned. 

The intine continues to grow and extend downward by 
the above described process till it reaches the ovule. It is 
yet a question of doubt whether the pollen tube enters the 
ovule or whether it simply comes in contact with it and the 
fertilizing fluid passes into the ovule by osmotic action. 

Pollen. — Laboratory Work. 

Select the pollen of some species of flower. That of the 
hedge bind weed is a good example to start with on account 
of its size and simple form. 

Place some pollen dust on a clean slide and cover with 
cover glass. Examine first with low power then with the 
J-inch obj. and B ocular. 



48 BIOLOGY. 

I 1 Form. 'Note carefully. 
2 1 Size. Measure carefully. 
3 1 Farts. 
I 2 Extine. 

I 3 Markings. Note carefully. Make drawings on 
good paper and keep for future reference and comparison. 
2 3 Color. 
2 2 Intine. Fress slightly on cover glass. This will rup- 
ture the extine and allow the intine to protrude. Note its 
extensibility and comparative toughness. 
3 2 Fertilizing fluid. 
I 3 Composition. 

1* Fat. Smash some pollen on a piece of paper. 
It will leave grease spots. 

2 4 Starch. Admit some solution of iodine under- 
cover glass and note results. 

Carefully examine twenty species of pollen in your vicin- 
ity before proceeding to the next. 



FERMENTATION.— (L.,ferveo, I boil.) 

Fermentation is a species of metabolic change in organic 
substances developed and maintained by the life action of 
low forms of micro-organisms called the germs of fermenta- 
tion, each fermentation caused by its peculiar germs. In fact, 
in noticing the similarity between fermentation and infectious 
diseases it was believed that the latter also are forms of fer- 
mentation. Henle, in 1840, expressed the belief that living 
organisms, probably of vegetable origin, were the cause of 
acute specific diseases. Bassi and Audouin, in 1838, had dis- 
covered the fungous nature of the muscardine disease in silk 
worms. In 1836, Schwan found that fermentation was caused 
by living cells apparently of vegetable origin. These investi- 
gations and discoveries led to two theories as to the cause of 
fermentation — 1st, the germ theory, and 2d, the physical 
theory. The germ theory, which is now accepted by the ma- 



BIOLOGY. 49 

jority of the scientific world, was first introduced by Astier, 
Schwan and Cagniard, and brought to its perfection by Pas- 
teur. It gives for the cause of all fermentations a micro- 
scopic germ. Alcoholic fermentation is taken as the typical 
example. It is caused by the sacharomyces or torula cere- 
msiae, a living organism which is always found where alco- 
holic fermentation takes place. These organisms are unicel- 
lular, multiplying by division. They require for their food 
sugar and nitrogen. The chief products of their life action 
are alcohol and carbon dioxide. The germ theory, during its 
infancy had powerful opponents. The principal ones were 
the believers in the physical theory and the advocates of 
spontaneous generation. The physical theory, started by 
Willis and perfected by Baron Liebig, teaches that fermenta- 
tion is due to peculiar molecular action, that is the molecules 
underwent motor decay. This molecular motion was capable 
of being transmitted to other unstable organic compounds. 
This action was called " catalysis" or ;; catalytic" action. 
(Gi\, kola, downwards; and lyo,l dissolve.) The physical 
theorist could not explain why the first molecule underwent 
motor decay any more than the germ theorist could explain 
the origin of the original organism or germ. Hence it is seen 
that Liebig and his followers accounted for fermentation with- 
out the intervention of bacteria. They acknowledged the 
presence of germs, but explained their presence by saying 
they were the result and not the cause of fermentation. 
Spontaneous generation was strongly advocated by the physi- 
cal theorists. Bastian affirmed that organic substances, hav- 
ing undergone molecular decay, will cause the origin de novo 
of certain fungi. The germ is present because the change 
wrought in the substance has made it the proper food for the 
germs to feed upon. A very simple experiment will show the 
fallacy of spontaneous generation. Take two flasks, both 
filled with organic substances capable of undergoing fermen- 
tation. Sterilize both by boiling so that there is a certainty 
that no living germs or spores are present, and hermetically 
seal one flask by means of the blowpipe. Let the other re- 



50 BIOLOGY. 

main open. After a time the open flask will contain numer- 
ous living organisms while the sealed flask will show no signs 
of life. 

Both theories have good arguments pro and con, but the 
germ theory has by far the greater claims for being the true 
theory. (1) Under no circumstances will fermentation take 
place without the presence of germs. (2) A given species 
of germ will always produce a certain kind of fermentation. 
(3) Introducing germs into a sterile substance will at once 
develop the process of fermentation. (4) Culture fluids have 
been made in which it could be demonstrated that none but 
a given species of germs were present. Such a culture 
fluid always caused its peculiar kind of fermentation. 



LIFE.— (A.-S., lif.) 

The great problem of life is as difficult of comprehension 
as it is important. What is life? There is no definition that 
is unassailable. The truth of this no one more fully realizes 
than the scientist. Our knowledge of life is too meager and 
the data from which to form conclusions are too few to give 
us a real conception of the relations of living substance 
to its surroundings. The definition given in the intro- 
duction to Biology is by no means perfect, nor is the 
one I am about to give. We might say that life is that 
relation of force to matter which produces a substance 
capable of a cyclical change. By this cyclical change is 
meant birth, growth, reproduction and death. These 
changes we observe in all living substances. The concep- 
tion of the first change is almost axiomatic. We can not 
conceive of a living substance without its being brought into 
existence. The idea of growth is closely related. Birth 
itself implies growth. The consideration of reproduction and 
death is more puzzling. It might be asked why does a living 
substance after a certain stage of development reproduce its 
kind and then die ? Why does not the original living sub- 



BIOLOGY. 51 

stance continue to evist without reproducing? It would es- 
sentially bring about the same final results. In all living cells 
we notice certain senile changes which finally render them 
incapable of performing their necessary function and death 
is the result* Why these changes take place is not known. 
It can be readily understood that death necessitates reproduc- 
tion, else the race could not exist. 

We notice certain conditions necessary to life. They are 
moisture, temperature, light and air. In all living matter we 
find a large amount of water in its composition. That this 
degree of moisture is considerable can be seen for example 
in the amoeba and human body. Absolutely dry matter is 
incapable of living or of producing life. It is easy enough 
to understand w T h} this should be. Living bodies must be 
more or less pliable that they may imbibe and assimilate food, 
that they may grow internally and that they may move about 
in search of food. (The extension of roots into the soil and 
of trunk and leaves into the air, and other movements may be 
considered as metabolic movements in plants.) Water being 
a very mobile substance will partially impart its mobility to 
those bodies containing it. Water does not go into chemical 
union with living bodies. It enters, exists in and leaves the 
body as w r ater. Many of the lower organisms, as the fungi, 
may bo reduced to a state of considerable dryness before life 
is destroyed. In this state they show T no signs of kinetic life 
and are to all appearances dead, but as soon as they are 
brought into contact with moisture and a certain degree of 
warmth they show signs of life. The actual amount of mois- 
ture required to maintain life varies in different organisms. 
The range of limit is quite narrow, for example, in man and 
quite broad in fungi. 

Temperature is closely associated with life. All vital 
phenomena of assimilation, movement, reproduction, etc., 
are manifest within a certain range of temperature. As 
temperature passes the limit of this range life ceases. The 
limit varies greatly with different organisms and with the 



52 BIOLOGY. 

amount of moisture present. Generally it is found that a 
greater degree of heat and cold can be borne when in a com- 
paratively dry state. Fungi have been exposed to a dry heat 
of 120° to 140° C without being killed while none are sup- 
posed to survive a temperature of 100° C when in a moist 
condition. No satisfactory experiments have been made 
upon higher animals. Here the conditions of life are so com- 
plex that it is very difficult to come to any definite conclu- 
sions. In regard to cold it has been found that the tempera- 
ture of torula could be reduced to — 60° or — 75° C in a dry 
state before life action ceased ; while in a moist state — 5° C 
was sufficient to kill them. It is known that some of the 
protozoons flourish in the snow and ice fields of the arctic 
regions and in high latitudes of the temperate zones. We 
also find diatoms in the arctic and antarctic seas. As a rule 
the maximum temperature which organism can bear is much 
less variable than the minimum. 

Light being so closely related to heat makes it at once 
easy to comprehend that it must be necessary to life. Though 
we find living organisms growing in absolute darkness, for 
example fungi, plants in dark cellars and some cave animals, 
though we find that light retards the growth of plants, yet 
they required light originally to bring them into existence. 
All living substances receive the influence of sunlight more 
or less, either directly or indirectly. It is known that light 
penetrates to some depth in soil and to a much greater depth 
in water. Most organisms living to some depth under the 
soil and water come to the surface more or less and are ex- 
posed to the sunlight. 

Spectrum analysis has shown us that light has caloric 
and actinic properties besides its well known luminous prop- 
erty. The most important chemical action that light exerts 
is in the growth of plants. The various organic compounds 
in the vegetable world owe their origin to the sunlight acting 
as a reducing agent. Chlorophyll and starch production 
cease almost wholly in its absence. Starch is supposed to be 



BIOLOGY. 53 

produced by the action of sunlight and chlorophyll ; others 
again claim that starch is formed by small bodies called 
leucoblasts. The best authorities seem to agree that starch 
originates in chlorophyll and other coloring substances, but 
mainly from these colorless starch generators called leuco- 
blasts. These are small and often hard to find. Iris Ger- 
manica affords a good example in which to search for and 
study them. 

Air is necessary to life because it consists of and holds 
in suspension those substances required to sustain life action. 
Free oxygen is taken up by all animals. Plants take up C 
2 , N H±, aqueous vapors, etc. Nitrogen acts only as a 
diluent, else oxydation would go on too rapidly. H 2 O holds 
air in solution for the fish and other water animals.* 

One must keep in mind the relationship of plants and 
animals. One is dependent on the other. Whatever is re- 
quired by one is also directly or indirectly required by the 
other. They both undergo a continual process of integration 
and disintegration, a continual change in form. In nature 
there is nothing independent. All combine to form links in 
an endless chain. 

As already stated, not the smallest particle of matter is 
lost or useless, neither is the expenditure of energy or force. 
The death of a plant or animal is only the act of giving 
nourishment to some living plant or animal. The kinetic 
energy of life in the present generation is finally stored as 
potential energy to be again converted into kinetic energy in 
some future generation. Thus force and matter are co-ex- 
istent, immutable and indestructible. + 

* Space does not permit a fuller discussion of moisture, tem- 
perature, light and air. The student is requested to freshen his 
memory on those subjects in some standard work on physics ; also 
the chemism of plant and animal life shouid be reviewed. 

t Some of my statements ar< i necessarily broad, hence the stu- 
dent is earnestly advised to do some independent thinking in order 
that he may comprehend and not be misled. Confucius has rightly 
said, " Study without thinking is labor lost." 



54 BIOLOGY. 

Having briefly considered some of the properties of life 
it might be well to consider its source and the relation of in- 
organic and organic matter. We have good reasons to be- 
lieve that at one time this earth was a large nebular mass 
revolving in space. At this time it consisted of elementary 
substances in a gaseous state. Where these substances came 
from is impossible to say. As already stated we can not well 
believe otherwise than that force and matter were co-existent 
and eternal, having no beginning and hence no end. This 
matter acted on by this peculiar force became arranged and 
rearranged. Finally the formation process made the environ- 
ments suitable for the production of inorganic compounds. 
The greatest factor to bring about these chemical combina- 
tions was heat. We can produce compounds artificially by 
causing elements to unite chemically on the application of 
heat. This chemism continued for ages till an exterior crust 
began to form. It will be unnecessary to state that at this 
time living matter could not exist. All the conditions were 
foreign to life as we know it. Water existed in the form of 
steam and vapor, the semi-solid crust was heated to a high 
temperature. By and by the temperature was sufficiently re- 
duced to allow the crust to harden and water began to con- 
dence in pools, seas and rivers. Now we have the foundation 
from which all subsequent life, vegetable and animal, sprang. 
The same forces that formed inorganic compounds out of the 
nebular mass continued to work and finally produced organic 
matter endowed with a life principle, (mind, consciousness, 
soul). This first life was produced from the inorganic com- 
pounds at hand. Xo new elements or compounds were added. 
Living matter contains the same elements that non-living 
matter contains. The life mystery (life principle) is to be 
sought for in the combination of these elements. 

Chemists have been able to produce organic and inorgan- 
ic compounds in the laboratory, but no chemist has so far 
been able to produce an organic compound endowed with a 
life principle, not even the simplest. Living matter is too 
complex for our present knowledge of chemistry. This life 



BIOLOGY. 55 

principle we find in all living matter — in the amoeba as well 
as in man. It has not been located in any particular part of 
the body. We know that it exists only from the fact that 
we can observe its manifestations. This life principle is the 
same in quality in all organisms. The only difference is that 
of quantity. 

The "instinct" of the dog is essentially the same kind 
of manifestation as the wonderful "reasoning" in man. The 
closer we study Biology the more are we convinced of that 
fact. 

Spontaneous generation has been the subject of much 
controversy. Its advocates had a strong following and still 
has a few great scholars who teach that under suitable con- 
ditions and surroundings some of the lowest forms of life can 
originate de nova, that is spontaneously. Yet, the more care- 
ful observers have been the more they are convinced that 
Virchow's dictum, "Omnis cellula ab cellula" is true. There 
has been no positive proof given that life, even the simplest, 
can or does originate spontaneously. If that be the case and 
admitting that the theory of evolution is true, where did the 
primordial germ or cell come from ? The only reasonable 
explanation is this : Though life does not originate spontan- 
eously now, some time in the past the conditions and en- 
vironments must have been suitable to develop a primordial 
germ or germs. This first living substance was no doubt 
aquatic, neither vegetable nor animal, of the simplest struc- 
ture, similar to our amoeba. It was the primal parent of all 
living matter. 

It must be borne in mind that the process of evolution 
has been at work or rather can be traced back to the remotest 
part of our earth's history. It formed a nebular mass; it 
formed inorganic and organic substances ; from these it de- 
veloped species after species, each succeeding generation 
more perfect than the preceding until the climax was reached 
in man. This process does not stop here. It will continue 
through all ages. We note changes to a higher perfection 



56 BIOLOGY. 

before our very eyes. The human race as a whole is pro- 
gressing ; the whole animal world develops more complex 
species ; the vegetable world produces more highly special- 
ized forms. Those structures that cannot fulfill the require- 
ments of the evolution theory become extinct. 

What is the life principle ( mind, soul, consciousness.) 
What is its source ? Is it something separate from the body ? 
The correct theory seems to be that the life principle is con- 
comitant with and dependent upon organization of matter. 
Matter must be combined and arranged as it is in the amoeba 
before it will manifest the life action of an amoeba. It must 
be arranged as it is in man before it can or will manifest a 
definite "reasoning" faculty. We find that the more highly 
developed an organism is the more highly developed is its 
life principle. A morbid change in the body produces a cor- 
responding change in the life principle. For example, com- 
pare the "soul" of a chronic dyspeptic with that of a man in 
good health. Since mind (life principle, consciousness) is the 
result of organization of matter it ceases with death or the 
disorganization of matter. 

In conclusion, I will give a schematic presentation of the 
development of animal and vegetable life according to the 
evolution theory. It is general and by no means perfect. It 
will be noticed that the animal kingdom is somewhat higher 
and later in development than the vegetable ; algae are higher 
than fungi, etc. 

Space is too limited in a small work like this to go into 
detail. The student is advised to read standard authors on 
the subject of Biology. Eemember the fact that you can not 
become a real scholar in any branch of science nnless you are 
in favor of free thought and unless you are willing to study 
wholly unbiased and unprejudiced by preconceived notions. 

About one week should be devoted to the study of life. Lect- 
ures by the professor in charge, supplemented by reading reference 
books m a good library are recommended. 



BIOLOGY. 



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58 BIOLOGY. 



YEAST, Torula Cerevisiae, (L., torus, a knot; and cere- 

visia, beer.) 

The torulse have long been known by their power of 
producing fermentation in sacharine substances. The whitish 
substance that collects on the surface and bottom of ferment- 
ing substances, for example, beer consists almost wholly 
of these organisms. They are microscopic cells, consist- 
ing of cell wall and cell contents, ranging in size from 
1-1,000 to 1-2,000 of an inch in diameter. A cubic inch of 
yeast may contain over a billion cells. Their structure is 
very simple, a comparatively tough cell wall and a trans- 
lucent, viscid protoplasmic fluid. In the smaller cells (the 
undeveloped younger cells) may be found a roundish more 
viscid portion, which is termed the nucleus or cytoblast (Gr., 
cytos, a cell ; and hlastos, germ). In reproduction the cyto- 
blast separates into two or more independent portions. These 
surround themselves with a membrane thus forming new 
cells. Reproduction goes on very rapidly. Sometimes a 
number will adhere together, forming a "string" or " group." 
Generally there is formed a more clear portion within some 
cells termed a "vacuole" (L., vacuus, empty) whose presence 
and function is not explained. 

On the addition of H 2 S 4 it is found that the cell wall 
has two coats, an external and internal. The internal coat, 
which resembles the intine in pollen, will contract with proto- 
plasm. The external coat remains unchanged. Chlorophyll 
is not present during any stage of its existence. Assimila- 
tion takes place by asmosis. The torulse, like the fungi, will 
multiply in the dark and in sunlight. 

Whether the torula belongs to the animal or vegetable 
kingdom is a question hard to decide. It contains no starch, 
no chlorophyll, it absorbs oxygen and gives off carbon 
dioxide, it exists and multiplies without sunlight ; these prop- 



BIOLOGY. 59 

erties would indicate that it was not a plant but a member of 
the animal kingdom. But the fact that the external cell wall 
consists of cellulose and that it has the power of forming 
protein out of a non-proteid compound, such as ammonium 
tartrate, makes it almost decidedly a plant. If the scientific 
world would permit we might class it with Haeckel's mowers 
or third kingdom. But the majority are satisfied to call it a 
plant, so it is probably better to adhere to their decision in 
order to avoid confusion. 

Laboratory Work. 

Wash a little yeast so that nothing but the cells remain. 
Place some on a slide and cover with cover glass. Examine 
with J-inch objective and B ocular. 

Yeast (Toruise). 

I 1 Size. 

I 2 Measure carefully with micrometer. 
2 2 Comparative size. (See note.) 
2 1 Structure. 

I 2 Cell wall or sac. 

I 3 Transparent, homogeneous. 
2 2 Protoplasm. 

I 3 Less transparent. 

2 3 Often dots more or less transparent. 

3 3 Vacuole, not always present. 

4 3 Cytoblast or nucleus. 

3 1 Form. 

I 2 Make drawings of five or six cells. 
4 1 Composition. 
I 2 Cell wall. 

I 3 Amit a little iodine solution under cover glass to 
which has been added a drop of II , S 4 . The sac stains 
bluish. This is the test for cellulose. 
2 2 Protoplasm. 

I 3 Iodine solution gives only a brownish discoloration, 
hence no starch is present. 



60 BIOLOGY. 

2 3 Add a drop of caustic soda and copper sulphate 
solution. A violet color proves that the protoplasm is a 
proteid substance. 
5 1 Physiology. 

I 2 Origin of torulae. 

I 3 Fill two flasks with culture fluid. Sterilize by boil- 
ing flasks, contents, cork and all. Hermetically seal one and 
allow the other to remain open. Examine the contents of 
open flask from time to time. It will soon be found that the 
open flask contains torulae. After a time open the sealed 
flask and examine. No torulae will be found. This proves 
that the torulae do not originate de novo. It proves very 
likely that torulae in a dry state float in the open air thus 
gaining access to the flask. Where did the original torula 
come from ? 

2 2 Growth of torulae. 

I 3 Fill three flasks, one with pure water, another with 
a 10 per cent, solution of sugar, the third with the culture 
fluid. Sterilize all three by heating to the boiling point for 
a short time. Add a little yeast to each. Set them aside and 
watch from time to time. In which flask does fermentation 
begin first ? In which is it the most active ? 

3 2 Life force of torulae. 

I 3 It is already known that boiling will destroy torulae. 

2 3 Fill three flasks with culture fluid. Keep them at 
different temperatures. One at 80° F., the other at about 
40° F., the third at about 15° F. In which is fermentation 
most active? 

3 3 Dry some yeast by a moderate temperature. This 
does not destroy its activity. 

Note. — Examine different kinds of yeast. Baker's 
yeast will probably be most easily procured. 



BIOLOGY. 61 

AMCEBA. — (Gr., amoeba, change.) 

The amoeba is very interesting because it represents the 
lowest form of animal life, consisting almost wholly of un- 
differentiated protoplasm. A description of its properties 
has been given in the introduction to Biology which the stu- 
dent is advised to re-read. Amoeba can generally be found 
in stagnant water containing decaying vegetable matter. An 
infusion of vegetable matter in water exposed to the sun- 
light will almost certainly contain amoeba, besides many 
other forms of protozoons. 

Amoeba are very simple in structure. The external limit- 
ing layer or ectosarc can not properly be called a distinct 
membrane any more than an oil globule can be said to have 
an external coat. The ectosarc is simply of a somewhat 
different consistence than the more internal portion. The 
protoplasm generally has numerous small granules scattered 
through it. Sometimes a clearer portion called the vacuole 
or contractile vesicle may be found in the protoplasm which 
generally contracts with great regularity. The function of 
this contractile vesicle is not definitely known. It is supposed 
to pump water in and out of the body. 

The amoeba is rarely at rest during life. Its continual 
change in position and form is due to its power of extending 
and retracting any portion of the ectosarc. These prolonga- 
tions are called pseudopodia, meaning " false feet." These 
pseudopodia enable the amoeba to move from place to place 
and aid in finding and grasping its food, and also aid in 
digesting it. 

The food of the amoeba consists mostly of vegetable 
organisms. It appropriates these by wrapping itself around 
them, thus making a temporary stomach of the ectosarc. As 
soon as it has assimilated all that it requires it unwraps itself, 
and allows the useless portions to float away. Some bi- 
ologists claim that the food passes through the ectosarc into 
the protoplasm and the undigested particles pass out through 
the same channel. 



62 BIOLOGY. 

The form of the amoeba when at rest is spherical. This 
may be proven by reducing the temperature to the freezing 
point or raising it to about 100° F., or by a moderate electri- 
cal shock. Either of these processes will render the amoeba 
powerless and leave it in a spherical form. A strong elec- 
trical shock will kill them. 



Laboratory Work. 

Place a drop of water containing amoeba on a slide. 
Cover with cover glass. Avoid pressure. Examine with 
J-inch objective and B ocular. 

Amoeba. 
I 1 Form. 

I 2 Note the continual change. 

2 2 Note the development of a pseudopodia. The ectos- 
arc prolongs first then the protoplasm follows after, often 
with a sudden rush. 

3 2 Make drawings at intervals of five seconds. 
2 1 Size. 

I 2 Different in different species. Measure several. 
3 1 Structure. 

I 2 Ectosarc. 

2 2 Nucleus. Sometimes absent. 

3 2 Vacuole or contractile vesicle. Note its slow dia- 
stole and rapid systole. 

4 2 Foreign bodies which have been swallowed. 

5 2 Admit some iodine solution. If there is any blue 
coloration it is due to starch granules which have been swal- 
lowed. 
4 1 Kinds. 

I 2 Look for encysted forms. Some come to rest spon- 
taneously, assume a spherical form and secrete around them- 
selves a structureless sac. 

2 2 One species has very long and slender pseudopodia. 

Note. — Compare the amoeba with white blood corpuscle. 



BIOLOGY. 63 



BLOOD CORPUSCLES. 



Place a drop of blood well diluted with water on a slide 
and cover with cover glass. 

Blood Corpuscles. (Human.) 

I 1 Red corpuscles. 

I 2 Relative number compared with white. Varies from 
600 to 1,000 in health. 
2 2 Form. 

I 3 General form, disk. 
2 3 Surface, concavo-convex on both sides. 
I 4 Convexity near margin. 
2* Concavity in center. 

3 4 Proof of form : If seen a little beyond the focus 
the center appears dark ; if a little within focus the margin 
appears dark. Due to the fact that the convex and concave 
surfaces can not be brought to a focus at the same time. 
3 2 Size. 

I 3 Measure carefully with micrometer. 
4 2 Color. 

I 3 En masse, red ; single corpuscles, pale yellow or al- 
most colorless. 

5 2 Movements. 

I 3 None, except probably Brownian. 
6 2 Tendency to collect in rolls (roleux.) 
7 2 Crenated margin on becoming dry. 
8 2 Nucleus. 

I 3 None visible. Some physiologists claim that the 
form of the red corpuscle is due to the contraction of its 
nucleus 

2 1 White corpuscles. 
I 2 Form. 

I s Spherical, changeable. 
2 2 Size. 

I 3 Measure with micrometer and comparative size. 
3 2 Motion. 



64 BIOLOGY. 

I 3 Amoeboid. Closely observe a corpuscle for a few 
minutes. The change in form takes place very slowly. Make 
drawings at intervals of one minute. 

4 2 Nucleus, generally present. 

5 2 Granular contents. 

Note 1. — Examine the blood of amphibians, birds, in- 
sects, etc., and make comparisons. 

Note 2. — The standard for finding comparative size of 
microscopic objects is the red corpuscle. 

Cappillary Circulation in Web of Frog's Foot. 

Catch an ordinary frog and put it in a bag just large 
enough to hold it with the exception of one hind leg. Sew 
the bag shut and tie it frog and all on a wooden stage in such 
a position that if the free extremity is extended the web of 
the foot will just come under the objective. By means of 
thread tie the foot with toes extended over the opening 
which you have made into the wooden stage for the trans- 
mission of light. Finally tie the whole on the stage of the 
microscope. 

The foot can not be tied so that it will remain absolutely 
quiet. 

(a) Focus carefully and make your observations while 
the frog is quiet. 

(b) Observe elasticity of red corpuscles, elongating and 
bending to adapt themselves to a given cappillary. 

(c) White corpuscles have a tendency to adhere to the 
sides of vessels and to migrate through the walls. 

(d) There is no visible difference between venous and 
arterial blood. Determine the difference by the direction of 
flow. 

(e) Observe effects of stimulants applied to frog and foot. 
Note. — There is no test known to science by means of 

which human blood can be unmistakably distinguished from 
all others. The spectroscope is said to have accomplished 
what heretofore has been impossible. 



BIOLOGY. 65 



MOUNTS FOR THE MICROSCOPE. 



TEMPORARY MOUNTS. 

Temporary mounts are such not intended for future ex. 
amination. The mode of preparing them depends on the 
substance to be examined, for example vegetable tissues can 
not be mounted like starch granules, nor pollen like blood 
corpuscles It would be impossible to describe each case in 
detail. Only some general advice can be given. Good 
judgment and reason will do the rest. 

(a) See that the slide and cover glass are perfectly clean 
and dry. 

(b) See that the substance to be mounted is free from as 
much foreign matter as possible. 

(c) Do not place a " hand full" of the substance on the 
slide, but only enough to show all the parts you wish to see. 
Be sure that you do not place it all in a nice heap in the cen- 
ter of slide, so as to make it impossible for light to pass 
through it. 

(d) The mediums most used for temporary mounts are 
waver and glycerine. Keep in mind the effect these mediums 
have upon the various substances for examination. The 
principal use of the medium is to dilute. For example if 
undiluted blood were placed on a slide it would be impossible 
to see separate corpuscles. 

(e) Place a cover glass (use only the circular) on the sub- 
stance. It retains the substance in place, spreads it evenly, 
and prevents the too rapid evaporation of the mounting 
medium. 

(f ) Bear in mind the effect of heat and cold on what is to 
be examined. 

(g) Remember that cleanliness is a virtue much to be 
desired in everything especially in microscopy. 



66 BIOLOGY. 

NEEDLE PREPARATIONS. 

Mounts prepared by means of needles, called dissecting 
needles, are termed needle preparations. They may be either 
temporary or permanent mounts. The skillful microscopist 
can do very satisfactory work by means of his dissecting 
needles, although the mounts may be lacking in the beauty 
of finish found in those cut with a microtome, 

(a) Prepare two dissecting needles by fastening two 
medium sized needles, heads down, into wooden handles of 
convenient size and length. The needles should be highly 
polished and sharp. If they are rusty it is almost impossible 
to work with them. If desirable they may be bent in any 
shape by first heating them to redness. 

(b) It is very essential that one should have a dissecting 
microscope/ There are a great variety in the market, for 
instance the " Handy dissecting microscope " of the Bauch 
& Lomb Optical Co., which I think can be had for one dol- 
lar. Their " Excelsior " with three lenses costs $2.75. If 
one has the means to make the investment it is best to get a 
good binocular. Any person, however, with a little ingenu- 
ity can construct a very creditable dissecting microscope for 
himself as follows : Take a sound block of wood an inch 
thick, four or five inches wide and about six or seven inches 
long. In the middle of one end of this block of wood which 
we will call the stand, place upright a heavy (J-inch) piece of 
wire about four or five inches long. Take a good large cork 
in which make two holes, one for the heavy wire in the stand 
and the other for a thinner wire which is to be bent so as to 
form a right angle with the heavy wire. The extremity of 
the second wire furtherest away from the cork is to be bent 
in a suitable shape to hold the lens. That is all that is neces- 
sary. By means of the cork you can focus up and down. 
By means of the second wire which works in the cork the 
lens may be swung from side to side. The lens of any sim- 
ple microscope can be used. A plate of glass may be placed 
on the stand so as to give a smooth clean surface to work on. 



BIOLOGY. 67 

Any kind of hand rests may be placed on either side of the 
stand. Having, by a little ingenuity and mechanical skill, 
devised the necessary apparatus you may begin preparing 
mounts. It can be readily seen that only soft tissues, such as 
muscle, tendon, fascia, etc., can be used. 

(a) Take a piece of tissue about the size of a pin head, 
place it on the glass plate of your dissecting microscope and 
begin to separate the ultimate fibres by means of your dis- 
secting needles. Keep the tissues moistened with an alkaline 
solution (Na CI sol.). Tease just as long as there is any thing 
left to tease. The ultimate fibres must be separated. It is a 
tedious task, but practice patience which you must do before 
you can become a microscopist or anything else. After be- 
ing convinced that the substance is sufficiently teased proceed 
to the next. 

(b) Remove as much moisture as possible by means of 
blotting paper. Drop a few drops of 85% alcohol on tissue, 
allow it to remain a few minutes, then remove by means of 
blotting paDer, The alcohol hardens and contracts the ulti- 
mate histological elements somewhat, thus making them more 
conspicuous under the microscope. It also prevents decom- 
position of tissues. 

(c) Now add a few drops of staining fluid. Carmine is 
probably the best for animal tissue. Allow it to remain till 
well stained. The object of the staining is not to make the 
mount appear more beautiful but to render the various histo- 
logical elements more prominent. The nucleolus stains more 
heavily than the nucleus, and the nucleus stains more heavily 
than the cell contents. Remove staining fluid by means of 
blotting paper. If stained too much wash out excess by 
means of washing bottle. 

(d) Fix the stain by allowing specimen to remain for a 
few minutes in acid alcohol. (See recipes). Remove alcohol. 

(e) Now put on a drop of oil of cloves. This makes 
the tissue transparent. Remove oil and dry the specimen 
in a moderate temperature. 



68 BIOLOGY. 

(f) Mount in balsam and finish like any permanent 
mount. 

Note 1. — Be careful not to have too much tissue on the 
slide. Remember that a very small particle will appear large 
under the microscope. 

Note 2. — Do not have the fibres all in a bunch but separ- 
ate them as much as possible. 

Note 3. — Do not be slovenly and careless. Good mounts 
can be kept for a long time. 

Preparing Animal Tissues to be Cut by Hand or with a 

Microtome. 

Some soft tissues can not be teased and mounted as has 
been described in the foregoing process. For example 
glandular tissues, such as liver, kidney and parotids ; also 
such tissues as lung, cartilage, muscular tissues with trichina 
in situ, etc. They require special preparation. It would be 
impossible to describe the best way for mounting each tissue. 
The student must keep in mind the nature and composition of 
the tissue he is about to work upon and the properties and 
actions of the various reagents he is going to use. 

The following process is general. Does not apply strict- 
ly to any one tissue. The different steps throughout this 
book are arranged with the supposition that the student 
spends at least one hour a day in the laboratory. 

preparing tissue for section cutting. 

(a) Preparing specimen. — Cut the tissues in pieces one 
inch square or less. Make either longitudal or transverse 
squares or both. Wash away blood, dirt, etc. Then place 
in a cold saturated solution of Hg Cl 2 Leave it one hour, 
then remove and wash free from all traces of the sublimate. 
(See recipes.) 



BIOLOGY. 69 

(b) Hardening. — Place in 65% alcohol for twenty-four 
hours. Then in 85% alcohol for twenty-four hours. Now ex- 
amine the tissue to see if it is nearly hard enough, if so place 
in 90% alcohol for one hour, [f not nearly hard enough, it 
must be allowed to stand for another twenty-four hours or 
more in fresh 85% alcohol. 

(c) Staining. — Place the tissue in the staining fluid twen- 
ty-four hours, till stained throughout. (Cut and see,) 

(d) Fixing the stain, — Place in 70% alcohol to which has 
been added a few drops of H CI. Leave an hour or so, till 
it turns a bright scarlet with carmine stain. It must not be 
stained too much. 

(e) Dehydrating. — Place in 70% alcohol for twenty-four 
hours. Remove and place in absolute alcohol for one hour. 

Clearing. — Place specimen in oil of cloves for twenty- 
four hours. The oil dissolves the alcohol and makes the 
tissue transparent. 

(f) Prepare for Imbedding. — Place the specimen in equal 
parts of oil of turpentine and paraffine heated over water 
bath for half an hour. Do not boil it. Then into paraffine 
heated over water or sand bath for one-half hour. 

(g) Imbedding. — Make a paper box suitable to the size 
of the specimen. Place in it the specimen, and imbed it in 
melted paraffine. 

Note 1. — This is one of the many ways of preparing a 
specimen for the microtome and probably one of the very 
best. The different steps are so arranged as to save you both 
time and extra labor. 

Note 2. — Observe each step and study out "why" you 
should do this and that. Remember that the various tissues 
treated alike will not give like result-. 



70 BIOLOGY. 

CUTTING SECTION. 

(a) Cutting with a microtome. 

(1) Make either transverse or longitudal sections. 

(2) Out as many sections as desired, and place in a 
clean box properly labelled. 

(b) Cutting by hand. 

(1) Do not cut too thick. 

(2) Hold the section firmly in the left hand, and draw 
the razor at full length, evenly and smoothly toward you. 

(3) Do not " saw off" a section. 

(4) Cut one section, look at it and if you think it is thin 
enough, mount it and see ; if not thin enough, discard it and 
try to do better the next time. 

(5) Keep razor and specimens dry and clean. 

(6) Last, but not least, keep your razor sharpened to 
the keenest edge. 

MOUNTING A SECTION. 

(a) Cleaning slide and cover glass. — Remove all foreign 
matter by proper agents. Wipe perfectly dry with a clean 
cloth. 

(b) Remove paraffine — Lay one end of cleansed slide on 
some eminence, so as to incline it about five degrees. Place 
a section near center of slide. By means of pipette drop 
some benzine on the upper edge of the slide and let it run 
down. Allow all paraffine to dissolve and wash away. 

(c) Removing benzine. — Remove as much benzine as 
possible by means of a dry cloth and blotting paper. 

(d) Drying. — Warm the slide with specimen moderately 
till dry and then place specimen on exact center of slide. 
Find exact center of slide by means of slide centerer. 



BIOLOGY. 71 

(e) Mounting. — Place a well cleaned cover glass on top 
of the section. Deposit a drop of balsam around the margin 
of the cover glass ; capillary attraction will draw it under 
and spread it evenly. Press slightly and carefully, per- 
pendicularly on the cover glass. 

(f) Examining the section. 

(1) Examine with low power, (1-inch) objective. See 
if it is of right thickness, and if it shows the proper arrange- 
ment of tissue. 

(2) Examine with high power, (J-inch) objective. See 
if it shows all the histological elements, cells, nucleus, nucleui, 
etc. If the section does not meet a microscopist's expecta- 
tions, remove from slide at once. 

(3) If it is a good section remove air bubbles from 
under cover glass by carefully heating over spirit lamp till 
bubbles escape. 

7th step. — Finishing. 

(a) If the section is a good one, lay it aside for several 
weeks, till balsam is dry; then remove all superfluous balsam 
by means of knife, alcohol, and dry cloth. 

(b) Place on a turntable and make a ring of oxide of 
zinc around the margin of the cover glass. It may be artisti- 
cally finished by means of colored varnishes. 

(c) Labelling. 

(1) Paste label on the right hand of the slide, (the up- 
per side). Put on name of section, whether cross section or 
longitudinal; below that, your name and date. 

(2) It is well to place label also on opposite end on 
which write reagents used: 1. What hardening agent. 2. Im- 
bedding material. 3. Staining fluid. 4. Mounting medium. 

Note 1. — When examining a slide under the microscope, 
try to see what there is to be seen. Do not merely satisfy a 



72 BIOLOGY. 

morbid curiosity. Study what is before you in some standard 
treatise on the subject. 

Note 2. — Examine first with low power, and then with 
high power. In using the microscope, handle with care. 
Learn to keep both eyes open and to use them alternately, so 
as not to ruin your right eye. 



VEGETABLE TISSUE. 

Raw material for this branch of study can be found 
everywhere. The vegetable kingdom furnishes more interest- 
ing object for study than all other classes put together. 
Starch, which is so plentifully distributed throughout the veg- 
etable kingdom, has been described elsewhere ; also pollen. 
Among the lowest forms of animal life are the algae. (L., 
alga, sea grass). They are easily procured and afford an in- 
teresting study. They grow in water and may be found in 
the ocean coloring its water, in rivers, lakes, ponds, ditches, 
etc. The green scum so often seen on the surface of stag- 
nant water consists of these small plants. Put some vege- 
table tissue in a beaker full of water and expose it for several 
days to the sunlight. It will contain a large number of algae. 

Laboratory Work. — Algce. 

Place a drop of water containing algae on a slide and 
cover with cover glass. Examine with ^-inch objective and 
B ocular. 
Algae. 
I 1 Kinds. 

I 2 Single celled or unicellular. 
I 3 As to form. 
1* Spindle like. 
2* Rod like. 
4 3 Spherical. 



BIOLOGY. 73 

2 2 Many celled or mubticeilular. 
I 3 Double celled. 

2 3 Those in which cells are united so as to form a 
string. Often very long. 

3 3 Those in which cells are united in a group. 

2 1 Structure of a single cell. 
I 2 Cell wall. 
2 2 Cell contents. 

3 1 Composition. 
■ I 2 Cell wall 

l 3 Cellulose. 

2 3 Earthy salts. 

2 2 Cell contents. 
I 3 Albumen. 

2 3 Coloring matter, generally colorophyll. 
3 3 Starch granules. 
4 3 Oily substance. 

4 1 Assimilation. 
I 2 Endosmosis. 

1 2 From the water in which they live they take in C 
2 and N H 4 . 

2 2 Exosmosis. 

1 3 Give off oxygen. 

2 3 Surround themselves with a slimy coat. 

5 1 Admit a drop of iodine solution under cover glass and 
note results. 

ft 1 Make exact drawings of the different kinds of algae. 

7 1 Take two beakers containing algfe, place one in the sun- 
light, the other in the dark. Note results. 

The following process for mounting vegetable tissue is 
general, hence the student must use judgment in what he is 



74 BIOLOGY. 

about to undertake. Vegetable tissue is plenty and easily 
procured and with care very nice mounts can be made. 

Preparing for Section Cutting. 

(a) Bleaching. — Get two wide mouthed ounce vials. Pro- 
vide one with a perforated rubber cork. In one vial place 
some Mn 2 and H CI, insert the rubber cork containing the 
short end of a U-shaped delivery tube. Pass the other end 
of the tube into the second vial containing; water and the 
vegetable tissue. Chlorine will now be generated. Mn 2 
+ (H Cl) 4 = Mn CI + (H 2 0) 2 + Cl 2 which bleaches the veg- 
etable tissue. Allow it to stand for twenty-four hours. 

(b) Eliminating chlorine. — Place the tissue in a solution 
of Na 2 S 3 (one part of Na 2 S 3 to 30 parts of H 2 O) for 
half an hour, then rinse thoroughly with pure water. 

(c) Keinove air from tissue, — Place it, immersed in 20% 
alcohol, under the receiver of an air pump. Pump till bubbles 
cease to be given off. Diluted alcohol prevents the forma- 
tion of algae and other vegetations. 

(d) Prepare for imbedding. — Dry by means of blotting 
paper, then dip into Davis' solution, withdraw and allow to 
drain on blotting paper till surface is dry. 

(e) Imbed, cut and mount same as animal tissue. Sec- 
tions must be cut as soon as possible, else the tissue will be- 
come too dry and hard to cut. Keep the sections in diluted 
alcohol (20%) till ready to mount, 

BONE. 

Bone on account of its hardness requires special prepara- 
tion. Beginners generally have good success in making a 
section of bone. The following process is probably the best 
for mounting a section of dry bone in which the lining mem- 



BIOLOGY. 75 



brane of the Haversian canals and lacunae has been destroyed 
and removed. 



L 

Preparing for Mounting. 

(a) Get a long bone. With a bone saw saw off some 
transverse and longitudinal sections making them as thin as 
possible. Make the sections from the compact portion ol,the 
bone. 

(b) Thin down the sections by means of an ordinary file. 

(c) Place the section between two u Washita" or sand 
stones and rub till the section is so thin as to bend of its own 
weight when one end is raised. The grinding surfaces of the 
stones and section must be kept moist all the time. Grind 
carefully. 

II. 
Mounting. 

(a) Boil some Canada balsam till it is quite thick. When 
cool place a drop of this balsam on a cover glass and allow it 
to cool till it is of the consistency of putty or butter, then 
imbed in it the section of bone. Place cover glass with 
section downward on exact center of slide. By pressure get 
rid of as much superfluous balsam as possible ; apply a little 
heat if necessary. If mounted in thin balsam the lacuna* 
will become tilled up and spoil the section. 

(b) Finish like any other permanent mount. 

Note. — Rock sections can be made in a similar way. 
They, however, require more care and patience. 



76 BIOLOGY. 

INSECT MOUNTS. 

Small insects can generally be mounted whole without 
any previous preparation since they are mostly transparent. 
Among these may be mentioned Acarus domesticm, young 
Pulex irritant, Acarus scabies, and especially the younger 
members of the genus Pediculi. 

The larger insects, such as flies, bees, beetles, spiders, 
etc., require careful dissection in order to gain a correct in- 
sight into the relative structure of the insect economy. It 
would be impossible to describe how to proceed in each in- 
dividual case. Experience comes by practice and the student 
will find that each subject becomes more and more easy, 
especially if, before commencing in haste with the needles 
and scissors, he will study the general arrangement of organs 
in hi 8 subject, by reference to some one or other of the many 
standard works in existence at any good library. 

The student will have no trouble in finding insects for 
dissection. Put no insect to any unnecessary pain. Kill it 
as soon as possible by means of chloroform, ether, or the 
cyanide of potassium bottle which is now so often used. 

Before beginning work be sure you have the necessary 
instruments such as dissecting case, dissecting microscope, 
dissecting needles and the necessary reagents. Now select 
some insect to begin with, for example the Gryllus domesticus 
or common cricket. 

I. 
Prepare for Dissecting. 

(a) Carefully study the insect before you, referring to 
some standard work. Be sure you know what it is and can 
classify and name it rightly. Be sure you understand its 
mode of living and the structure of its organs. In fact find 
out all you can about it before beginning to dissect. Of 
course while doing this you will very dilligently use a good 
pocket lens and finally make a good drawing of the whole 
insect. 



BIOLOGY. 77 

(b) By means of knife, scissors and forceps, detach wings, 
legs, autennse, eyes, tongue. Portions of these if trans- 
parent 'enough can be mounted, otherwise they can only be 
examined as opaque objects. For example never have a 
mount which shows the foot of an insect very beautifully and 
has attached to it those portions of the leg which are much 
too thick and opaque to show anything at all, 

(c) Place the carcass of the insect back down on a slide 
containing a drop of hardened balsam. Allow it to become 
firmly fixed. 

(d) With a pair of fine scissors carefully slit up the in- 
tegument on both sides. Raise up the chitinous skeleton and 
clear away the attachments with a blunt needle. When this 
is tolerably well performed the whole of the organs may be 
seen in situ. 

(e) The specimen should now be placed for twenty-four 
hours in a mixture of glycerine and water (one of glycerine 
and two of water). This softens it for better dissection. 

Note. — In this operation it is supposed you are about 
to dissect out the digestive organs. If the nervous system 
were wanted it would not do to immerse it in a glycerine so- 
lution as that would only soften the already too delicate 
tissue more. Instead it would have to be immersed in 
dilute alcohol. 

II. 

Dissecting. 

(a) Place the specimen, still imbedded on the slide, in a 

dissecting trough under the microscope. For dissecting trough 

you can use any low dish or pan. Keep the specimen moist 

with the glycerine solution. 

(l)i Brush away all loose tissues with a small camel's hair 
brush. With scissors, needles and brush separate and clear 
away all that does uot belong to the digestive organs. Never 
allow the specimen to become dry. 



78 BIOLOGY. 

(c) By means of the scissors lav open the gizzard and 
wash it out with wash bottle and brush. 

III. 

Mounting. 
(aj Place the different organs in their natural position on 
center of slide. By means of blotting paper remove as much 
moisture as possible. Do not allow the specimen to become 
dry. 

(b) Mount in pure glycerine. Glycerine mounts require 
careful preparation. Care is required to prevent them from 
leaking. 

(c) Attach cover glass to slide by making around it a ring 
of balsam. After some time finish with varnish, etc. 



GENERAL ADVICE. 

Some advice has already been given about finishing bal- 
sam mounts. By careful study and consideration the observ- 
ing student will find the best way to finish any mount he may 
have. 

The intrinsic value of a mount does not depend upon its 
artistic finish ; but first, upon the fact that the section itself 
has real value. For example the digestive organs afford more 
interest than simply the chituous skeleton, although it may be 
entire and look very beautiful. Secondly, upon the fact that 
it is well finished so that it can be kept as long as possible, 
[f combined with these two qualities we can have beautiful 
finish so much the better. 

Always label each slide carefully. It avoids confusion 
and much unnecessary labor. Labels are cheap, get a good 
supply and paste them on well. In labelling insects always 
put on the scientific name, giving genus and species. If there 
is room you may put on the common name also. 

Do not throw mounted slides into any box like marbles. 
Such a procedure will soon ruin them if they were ever worth 



BIOLOGY. 79 

any thing. Place them in order in slide boxes made for that 
purpose. Place slides so that when the box is opened the 
labels naming the mounts will appear on the right hand side. 

Be sure that each box is properly labelled and classified 
and that all the boxes have a suitable case in which they can 
be kept. One box might be labelled as follows : 

Series No. 5. 
Digestive and Tracheal Systems. 
Articulata, (Subkingdomi. 

Insecta, (Class). 

Diptera, (Order). 

Muscadae, (Family). 

Genus and species are given on the label on slide. Or, 

Series No. S. 
Animal Tissues. 
Muscle and Tendon, 
Needle Preparation. 
Each slide box is made to hold twenty-five slides. In 
getting slides it is best to buy those with ground edges as they 
will not scratch your microscope. 

Above all keep only good mounts. Poor ones are of no 
use to you or any one else. Do not become discouraged if 
you fail in the first dozen attempts. If you have any ability 
at all you will finally come out victorious with a good mount. 
Study your slides thoroughly and carefully. Be sure you 
know what you have before you. Get the necessary books 
in some way. One thing that the beginner generally hicks is 
application. Keep your mind fixed on what is before you. 

Get your drawing outfit and make drawings of what 
you examine. It will help wonderfully to bring out details 
and to fix them upon your mind. 

BACTERIA. 

In recent years much has been said and written about 
the role that the verv innocent and harmless looking bacteria 



80 EIOLOGY. 

is supposed to play in the animal economy. In some in- 
stances it has been proven with almost a certainty that they 
are capable of causing morbid changes in the natural cell 
function of the animal system, thus producing what is called 
disease. 

Bacteria are very minute, consisting of protoplasmic 
matter devoid of chlorophyll, generally multiplying by trans- 
verse division. They are of different forms, oblong, globu- 
lar, rod like, spiral, etc. Many exist in two kinds of condi- 
tions, a still and an active. 

Like torulae they are capable of exciting fermentative 
changes in substances in which they live. All the putre- 
factive changes in animal and vegetable bodies are brought 
about by these bacteria. Here again we find the truth veri- 
fied that death of one organism means life to another. 

Drying does not kill bacteria. In the dry state they are 
not active but as soon as they find a suitable nidus they will 
begin to be active and reproduce their kind. The air, water, 
and surface of the earth are supposed to be full of bacteria. 
The reasons why their evil influence on bodies is only felt at 
certain times are these: First, they may not be present in 
sufficient number; and second, the body upon which they are 
acting may not be in a suitable condition. Organic cells in a 
normal state have sufficient physiological resistence to with- 
stand the attacks of these germs. But as soon as this physi- 
ological resistence is lowered, for example in the human 
body by improper diet, the germs are able to locate and feed 
upon such cells, thus producing a pathological condition of 
an organ or some disease, as diphtheria, that depending upon 
the majority of germs which attack the body at the proper 
moment. 

On account of the small size of most bacteria the be- 
ginner is not able to accomplish very much. 

Laboratory Work. 
Infuse some hay in warm water for an hour. Filter and 
set the filtrate aside for twenty-four hours. Note changes. 



BIOLOGY. 81 

Examine the infusion with J-ineh objective and B ocular. 

Bacteria. 
I 1 Form. 

I 2 Rodlike or elliptic. 
2 1 Size. 

I 2 Several times longer than broad. 
3 1 Structure. 

I 2 Not much to be made out with such low power. An 
external transparent layer and the internal protoplasmic fluid 
containing darker substances, 

4 1 Movements. 

I 2 Some active, some passive. 

2 2 Some imbedded motionless groups. 

Bacillus. 
I 1 Longer than bacteria. 

Spirochaeta. 
' l 1 Form. 

I 2 Like a spiral thread. 
2 1 Motion. 

I 2 Very active. Spiral movement upon its longitudinal 
axis. 

3 1 Uncommon form, often found in decaying teeth. 

Place some hay infusion in three flasks. Boil two of 
them for a few minutes and hermetically seal one. Set all 
fchree aside in a warm place. Compare the three flasks. Ex- 
plain. 



EECIPES. 



No. 1. 
Davis' Solution. 



^ 



Acaciae Gummi . . gr. LX. 

Glycerine gtt. V. 

Alcoholi gtt. X. 

Aquse, ad Sii. 

Allow all the gum arabic 
to dissolve, then tilter care- 
fully. 

No. 2. 

Sulphite of Sodium . . 5ii. 

Aquae, ad §iv. 

Allow all of the No. 2 SO s 
to dissolve, then tilter. 



^ 



No. 3. 
Ohlmacher's Medium. 



Canada balsam Si. 

Chloroform Si- 
Mix and shake well. If too 
thick add more chloroform. 

No. tt. 
Corrosive Sublimate Solution. 

Aquae 01, 

Hydrargiri Chloridi cor. q.s. 
Make a saturated solution 
and filter carefully. It is a 
very powerful poison. As an 
antidote give albumen, the | 
white of an egg, flour, milk, ! 
etc. Give an active emetic. 



No. o. 
Iodine Solution. 



R 



Iodine gr. XL. 

Iodine Pottasium, gr. LX. 

Water ad Oi. 

Dissolve the two first named 
substances in Siv. of water, 
then add the remainder, filter. 



9 



No. 6. 
Gum Water. 



Gum Arabic 5iv. 

Glycerine gtt x. 

Carbolic Acid gtt v. 

Aquae, ad 5iv. 

This is an excellent medi- 
um for attaching labels to 
glass. 

No. 7, 
JPicro Carmine. 
11 

Carmine Powder, gr. XV. 
Liquor Ammonia, Si- 

Distilled Water, §VI£. 

Mix and add Picric-acid 
Powder 51 i- Shake well and 
filter. Now set aside for sev- 
eral days to evaporate. The 
powdered residue must be 
kept in a well stopped bottle. 

When ready for use take of 
the above Picro-Carmine pow- 
der 30 gr. and distilled water 
3-J- ounces, shake and filter. 



RECIPES. 



83 



R 



No. 8. 
Ammonia Carmine. 



Carmine Powder Si. 

Liquor Ammonia . . . Sss. 

While stirring add distilled 
water 5XY., filter and keep 
in a well closed bottle. 

No. 9. 
Preservative Fluid for In- 
R sects. 

Chloral Hydrate.. Si. 
Sodium' Chloride. . gr. xv. 
Pottassium Nitrate, gr. xxx. 
Glycerine and Alco- 
hol aa_ Ooiss. 

Water oz. v. 

Dissolve the chloral in the 
water and the remainder sep- 
arate. Mix and filter. 

No. 10. 
Culture Fluid for Torulae. 



R 



Potass. Phosphate, gr. X. 
Magnesium Sulph., gr. V. 
Ammonium Tartarate, -Si- 
Cane Sugar Siss. 

Water 5iv. 

Mix and filter. 



No. 11. 
Acid Alcohol. 



9 



Alcohol 
H. CI.. 



Sii. 
rttX. 



No. 12. 

Finishing Varn ishes. 

(For colored rings.) 

They are made by mixing 
the various colors with the 
vehicle in a mortar. 



VEHICLE. 

Dammar Gum 

Mastic Gum 

Benzine 



oz. in. 

oz. i. 

oz. vi. 



COLORS. 

White Oxide of Zinc. 

Blue Ultramarine. 

Red Carmine. 

Black Lamp-black. 

Green Verdigris. 

Yellow Chrome yellow. 

When the benzine evapo- 
rates it leaves the colors in a 
powder. Either use more 
benzine or simply dip the 
brush in benzine. 



It is best to buy the staining fluids all ready prepared, 
especially where only a small quantity is required. The re- 
maining formulae the student will have no trouble in prepar- 
ing for himself. 



VEGETABLE HISTOLOGY. 



Having considered the process of making sections for 
the microscope we shall now describe somewhat the general 
histology of vegetable tissue. Distinct tissue are not found 
in the lower plants, not till we arrive at the pteridophyta. 
(ferns, cycads.) The most important tissue is the vascular. 
This begins to develop in the highest bryophyta (moss) 
but can not be said to be fully developed till w r e get 
to the ferns and flowering plants. Epidermal tissues is first 
to be differentiated. It constitutes the primary covering of 
the plant, consisting of one, but sometimes of two or three 
layers ot cells. In it are found the stomata and trichome 
elements, which are simply modified epidermal cells. Scler- 
enchyraa or sclerotic tissue consists of cells whose walls are 
very much thickened, commonly called stone cells. Collen- 
chyma is a tissue whose cells have very much thickened 
angles; the cells themselves are generally prismatic in form 
and always found in close proximity to epidermal tissues. 
Cork tissue is also found beneath the epidermal tissue ; its 
cells are thin walled, there are no intercellular spaces and at 
maturity lose all their protoplasm and become filled with air. 

All these tissues, no matter how much they may differ, 
originated from a single parent cell. A general description 
of the cell is now in order. Heretofore the cell was con 
sidered the unit of structure in living organisms, this is prob- 
ably not so, as 1 shall explain later on. Generally the cell is 



86 VEGETABLE HISTOLOGY. 

defined as a neucleated mass of protoplasm. Sometimes 
even the nucleus may be absent so far as we know. In such 
cells it is supposed that the nucleus is finely divided and dis- 
tributed through the protoplasm. Cell, is an unlucky term 
since it conveys the idea of an enclosure. The early histolo- 
gists supposed all cells to be simply closed sacs and the very 
subordinate nature of the cell wall was not understood. We 
now know that the protoplasm and not the cell wall consti- 
tutes the essential part of the cell. In most cells we find sus- 
pended in the protoplasm a more highly refractive body, the 
nucleus. It consists of a delicate network of fibres suspend- 
ed in a more clear substance surrounded by a delicate mem- 
brane. The clear portion is called achromatin and the net 
work chromatin. The readiness with which the nucleus 
stains is due to the chromatin. The achromatin does not stain 
as readily, some staining fluids do not stain it at all. In the 
chromatin is imbedded a highly refractive body, the nucleo- 
lus. It is simply a more dense collection of chromatin. As 
a rule there is but one, but several may be found in some 
cases. Sometimes a nucleus is found within the nucleolus. 
McMillan has discovered imbedded in the nucleus certain 
highly refractive bodies very difficult to stain. Their function 
and presence is not yet accounted for. The fact is there are 
yet many mysteries of cell structure to be unraveled and 
many more will be discovered. 

The cell wall is secreted by the protoplasm and consists 
principally of cellulose in the vegetable kingdom. It is an 
amyloid carbohydrate having the same formula as starch. 

The thickness of the cell wall varies greatly. Sometimes 
peculiar regular markings are formed by this thickening pro- 
cess going on unevenly, depositing the cellulose in heaps as 
we find in pollen. Sometimes the deposits are formed on 
the inner surface of cells as in ring, spiral and pittet vessels. 
In cells that become free just before maturity (as in pollen) 
these markings are formed on the outer surface of cell wall ; 
when cells unite to form tissues the markings occur on inner 



VEGETABLE HISTOLOGY. 87 

surface as in the different vessels of the vascular bundles. 
Sometimes the cell wall becomes otherwise, changed in ap- 
pearance and chemical behavior as in cork and lignin (wood). 
It may become infiltrated with coloring matter and mineral 
salts. The outer portion of wall may become converted into 
mucilage or gum as in the quince seed or flax. Sometimes 
the wall becomes partially or entirely absorbed due to pres- 
sure of cells upon each other as in the formation of laticifer- 
ous tubes for example. These changes in the cell walls are 
of considerable commercial importance, yielding gums and 
resins besides other useful substances. Crystals of various 
kinds also occur in the cell wall, yet these crystals are mostly 
found in the cell contents. Infiltration of mineral matter, 
especially Si 2 , for the purpose of strengthening the cell 
wall often occurs, especially in grasses. 

Pfeffer claims that the cell wall, in fact nearly all tissues, 
are made up of small particles which he terms " micellae"; 
they are very minute crystalloidal particles, each one consist- 
ing of many molecules, yet too small to be seen with the aid 
of the best microscope. These particles are not in contact, 
but separated from each other by a layer of water. This 
water is taken up and held in place by capillary force. The 
increase in size of tissues on the addition of water is due to 
the fact that the layer of water is increased thus forcing the 
''micellae" further apart ; when the water evaporates the mi- 
cellae approach each other and cause the cell to shrink. 
Starch granules, coloring bodies, etc., are likewise said to be 
made up of these micellae. Pfeffer's assumptions are so far 
purely hypothetical. I have simply mentioned it to let the 
student know that there is such a hypothesis maintained by 
one of the greatest botanists. 

Protoplasm is the most important part of the cell. It is 
the basis of all living matter. Vet in spite of its importance 
but little is known concerning it. Typical protoplasm is a 
transparent, semifluid or viscid, granular substance*. It con- 



88 VEGETABLE HISTOLOGY. 

tains the elements C, O, H, N, some S & P. These combine 
to form very complex proteid compounds whose percentage 
composition is not known. These compounds are quite un- 
stable and can readily be broken up into simpler compounds. 

The properties of protoplasm may be divided into four 
kinds, namely, 

1. Ohemism. 

2. Metabolism. 

3. Motility. 

4. Reproduction. 

These properties are found in all living protoplasm and 
distinguish it from dead matter. All the phenomena of life 
action are dependent upon these properties. Chemism may 
be defined as the property which protoplasm has of produc- 
ing within itself spontaneous chemical action thereby chang- 
ing its chemical equilibrium. This chemism continues during 
the whole life period of every particle of protoplasm. Ces- 
sation of chemism means death to the protoplasm. The 
cause of this chemism is not known. 

Metabolism is the process of assimilation and the excre- 
tion of waste products. It is the result of chemism. 
Through this metabolic process protoplasm increases in 
amount and forms the many bi-products, such as cellulose, 
starch, chromatophores (coloring bodies), aleuron grains, etc., 
and the waste products which are no longer of service to the 
cell. 

Motility is that property which protoplasm has of pro- 
ducing within itself amoeboid and other movements. This is 
also dependent upon chemism. Berthold made a careful 
study of protoplasmic motion and explains it wholly mechani- 
cally. In order to understand him a careful study of surface 
tension is necessary. (The student is referred to any stand- 
ard college text on physics). Before a liquid or semi-liquid, 
free or suspended in another liquid, can come to rest or as- 



VEGETABLE HISTOLOGY. 89 

sume a fixed form, surface tension must be equalized or 
counteracted on all sides. Movements of oil globules sus- 
pended in liquids, which are quite common, are due to a dif- 
ference of surface tension between the oil globule and the 
liquid. As soon as surface tension is equalized movements 
of all kinds cease. If by some means the surface tension is 
continually changed motion is continuous. In living proto- 
plasm chemism is the property which continually produces a 
difference in surface tension and hence movements of various 
kinds are the result. The movements of amoeba, white blood 
corpuscle, bacteria, most infusoria, desmidia,alg8e, and stream- 
ing movements in vegetable cells are explained on this basis. 

Reproduction is the property which one particle of pro- 
toplasm has of spontaneously separating into two independ- 
ent masses. This will be more fully discussed under cell 
division. • 

R. Hartig has recently advanced a hypothesis which if 
correct will explain the source of protoplasm. By treating 
protoplasm with KHO or NaHO it is dissolved and leaves 
behind minute highly refractive bacterioid bodies which he 
terms "Zell Granula" or " Elementar Organismen," He 
claims that they are living organisms and by their life action 
secrete the protoplasm in which they live. This secreted 
protoplasm is not a waste product but is really a part of these 
organisms, as much so as the gelatinuous covering of bacteria 
or the shell of molusca. If this hypothesis be true then the 
cell is not the imit of structure but each cell consists of a 
multitude of simpler wn/its^ the " Zell Granula," which pro- 
duce protoplasm. 

Cell division takes place by two methods, direct and in- 
direct. The direct method is rare and occurs only in the 
lowest organisms. Here the nucleus constricts and separates 
into two, finally the whole cell is divided into two. In the 
indirect method the nucleus undergoes a peculiar transforma- 
tion before it divides, called karvokinesis. It is but very re- 



90 VEGETABLE HISTOLOGY. 

cently that karyokinesis has been studied and explained. 
Roughly it might be described as follows : (1) Nucleoli dis- 
appear. (2) Chromatin threads break up into U-shaped 
pieces. (3) Cross striations, which are present in the chro- 
matin, disappear, (4) U-shaped pieces arrange themselves 
so that the closed ends are placed perpendicular to the equa- 
torial plane of nucleus. (5) Appearance of two achromatin 
poles diametrically opposite and at right angles to equator. 
(6) U-shaped pieces each separate into two, one part passes 
to one pole the second part passes to other pole. (7) Reap- 
pearance of cross striations in chromatin. (8) Reappearance 
of nucleoi and cell division is complete. While this process 
has been going on in the nucleus the protoplasm and cell wall 
also became constricted through the middle and finally 
divided. 

In the cell are also found cell sap, leucoblasts or amylo- 
blasts which are supposed to form starch, aleuron grains 
containing crystalloid bodies, starch, acids, fixed oils, volatile 
oils, gums, resins, sugar, ferments, crystals, especially of 
calcium oxalate, coloring matter of which chlorophyll is most 
common, aromatic compounds and many other substances. 

TISSUES. 

As already stated all tissues develop from a single cell. 
Even after cell division has gone on to considerable extent 
no noticable differentiation of structure takes place. Sooner 
or later three primary meristematic tissues can be seen, 
namely, dermatogen, periblem and plerome. These can be 
studied in very young growing rootlets of ferns and angio 
sperms. Select the smallest fern rootlet obtainable and 
mount whole in water. It will show a structure something 
like that in Fig 4, lower right hand comer, c, is the tri- 
angular apical cell from which all tissues arise ; a, is the root 
cap which serves to protect the growing point of roots ; b, in- 
dicates the dermatogen, the primary epidermis, from which 



VEGETABLE HISTOLOGY. 91 

all epidermal structures develop : e, represents the periblem 
from which the ground tissue or parenchyma proper develops ; 
d, is the plerome cylinder or primary vascular bundle system. 
In the dicotyledonous angiosperms tissues develop from a 
group of apical cells. Study these primary tissues in the 
rootlets of ferns, monocotyledons and dicotyledons. 

The principal tissues are — 

(a) Vascular tissue or ducts. 

(1) Ringed vessels. 

(2) Spiral vessels. 

(3) Pitted vessels. 

(4) Reticulated vessels, 

(b) Parenchyma or ground tissue. 

(c) Collenchyma or thick angled tissue. 

(d) Sclerenchyma or stony tissue. 

(e) Liber or wood tissue. (Xylem.) 

(f) Tracheids or vasiform tissue. 
• (g) Sive tissue with sive plates. 

(h) Super or corky tissue. (Lenticels). 
(i) Laticiferous or milk tissue, 
(j) Epidermal tissue. 

(1) Stomata, water pores. 

(2) Trichomes, wax, warts. 

We shall first describe the vascular bundle system. This 
constitutes the frame work of plants. It serves to strengthen 
and also to conduct fluids utilized by plants. The cells com- 
posing it generally have thickened walls and are- much 
elongated in the direction of growth. The ducts or vessels 
constitutes the xylem or woody portion of the vascular bundle, 
the remainder consists of comparatively soft walled cells 
called phloem. The whole bundle is separated from the sur- 
rounding tissue by a sheath made up of cells having their 
walls thickened {xylem). 

There are three kinds of vascular bundles according to 
the arrangement of the xylem and phloem, namely, collateral, 



92 VEGETABLE HISTOLOGY. 

concentric and radical. In the collateral the xylem and 
phloem are placed side by side, the xylem toward the interior 
and phloem toward the exterior. Sometimes there is but one 
mass of xylem to two of phloem. This is called a bi-collater- 
al bundle. When the growing line is between the xylem and 
phloem as in woody dicotyledons, thus causing the bundle to 
grow in thickness it is called an open collateral bundle. 
When the bundle soon reaches a definite size, as in most 
monocotyledons, it is called a closed collateral bundle. The 
concentric vas. bundle has either xylem or phloem located 
centrally and surrounded by the other. Sometimes the xylem 
is located centrally as in ferns. In many of the monocoty- 
ledons the reverse is true. 



In the radical vascular bundle the xylem tissues or plates 
are arranged radially and separated from each other by 
phloem. The whole is surrounded by a bundle sheath. 
Sometimes the xylem plates meet in the center and sometimes 
they are connected by a pithy central cylinder of parenchy- 
ma. 



The common corn stalk is a good object in which to 
study the closed vascular bundle. Cut the stalk across at the 
internode. The vascular bundles can be seen by the naked 
eye as dots distributed through the stalk. This is a peculiar- 
ity of the monocotyledons. Now make a thin cross section 
and stain with chloriodide of zinc and examine first with low 
power. The sheath, 6 in fig. 1, consists of lignified paren- 
chyma cells. (Fig. 1 shows only one bundle.) These take a 
red-brown stain. 



VEGETABLE HISTOLOGY. 



93 



>i $1 




VASCULAR BUNDLE OF CORN STALK. 

1, Pitted vessels ; 2, ringed vessels ; 3, intercellular passage ; 4, 
parenchyma ; 5, reticulated cells ; 6, sheath or endoderm ; 7, sive 
plate ; 8, conducting cells, x 140. 

The intercellular spaces, as at 3, may be formed by two 
ways, either by the rupturing of cells or by their separation 
from each other. The first may be called the "lysignian" 
and the second the "schizoginian" method. The ring vessels 
are the first elements formed in the vascular system. 1, rep- 

nts pitted vessels. Sometimes a projection is seen on the 
inner wall of these vessels, it is all that remains of the divi- 
sion wall between the cells. Surrounding these ringed and 
pitted vessels are reticulated, thin walled cells, 5, these take 
a yellow-brown stain. The various vessels constitute the 
xyjem portion of the bundle. 

The remaining portion containing the sive tubes, 7, 
and conducting cells, 8, is called the bast or phloem portion 



94 



VEGETABLE HISTOLOGY. 



of the bundle. This takes a distinct violet stain with chlorio- 
dide of zinc. Sive tubes are never wanting. They are some- 
what large, long, thin-walled cells whose partition walls are 
perforated. Since the cells are quite long a cross section 
may show but few of these perforated cell walls, called sive 
plates. Notice that the xylem portion of bundle is toward 
the interior of stem and phloem toward exterior. Also to- 
ward outer side of stem the vascular bundles are more nu- 
merous and the intercellular passages are no longer found 
and the sheath is very much enlarged. Sometimes several 
bundles unite laterally. 

After having carefully studied the vascular bundles next 
examine the epidermis. Just beneath the extreme outer layer 
which contains the stomata is found a stout ring of ligneous 
(xylem, woody) tissue, this takes the same stain as the bundle 
sheath. The vas. bundles with their sheaths are so placed as 
to give the greatest possible strength to the stem. They con- 
stitute a system of compound pillars. 

Now make longitudinal sections, both radial and tang- 
ential. A radial section is made by cutting through circum- 
ference and center of stem ; a tangential section is made in 
any direction excepting through or toward center. Fig. 2 
represents a portion of vascular bundle of Zea mays. The 



//- 




LONGITUDINAL SECTION OF ZEA MAYS. 



VEGETABLE HISTOLOGY. 95 

numberings are the same as in fig. 1. ± is the parenchyma ; 
6, the sheath whose cells are generally more elongated than 
those shown in cut. 9, is a pitted vessel. Study carefully 
the sive tubes 7. 10, represents a sive plate ; 11, a mucil- 
age string found in all sive tubes. Sive tissue constitutes the 
nerve system of plants ; it plays an important part in the 
irritable movements of plants as shown by the investigations 
of Frank and others. Stain both transverse and longitudinal 
sections with coralline. This is an excellent stain to bring 
out the walls of vessels and rings. It stains xylem and 
phloem different tints ; xylem a bright coralline red and 
phloem a rose color. Tinct. of iodine stains ligneous tissue 
quite readily but does not stain bast fibres It will also show 
whether starch be present. 

Next make a cross section of outer part of cucumber 
stem. If you are lucky the section will show all the struc- 
tures shown in 'fig. 3. More likely, however, you will find 
it necessary to make several sections before all the different 
tissues can be found. Use the same stains used in the corn 
stalk sections. 1, represents the epidermis consisting of one 
layer of cells devoid of chlorophyll ; 2, is the collenchyma 
layer made up of thick angled cells. The cells themselves 
are prismatic in form. Collenchyma is always found in close 
proximity to epidermis. 

It serves principally to give strength and resistance to 
the outer portion of stem. Sometimes it forms a continuous 
ring beneath the epidermis, sometimes only in bands as in 
the stem of Yellow Dock for example. The lines of de- 
marcation between the different tissues are not so well marked 
as a rule as shown in the figure. 3, represents chlorophyll 
bearing rind parenchyma. 4, is sclerenchyma tissue*. The 
walls of its cells are very much thickened, e, in fig. 4,repre- 



The student is expected to make careful drawings of what he 
sees under the microscope. Use hard lead pencils on good unruled 
paper. 



96 



VEGETABLE HISTOLOGY. 

3 dfyM 







SECTION OF PART OF CUCUMBER STEM. 

1, Epidermis ; 2, collenchyma ; 3, rind parenchyma ; 4, scleren- 
chyma ; 5, parenchyma; 6, trichomes (hair cells); 7, wart ; 8, en- 
larged hair cell showing protoplasmic movement, a, chromato- 
phores, b, nucleus, c, protoplasmic strings, arrows indicate direction 
of protoplasmic current ; 9, air space beneath stomata ; 10, stoma, 
guard cells ; B, surface view of stoma. 

sents typical sclerenchyma cells as formd in the shell of nuts, 
here the cell cavity is almost obliterated. 5, is the true par- 
enchyma consisting of large thin walled cells. 6, shows two 
hair cells (trichomes), one has a pointed end the other 
knobbed. These hair cells are very numerous in some plants 
and are quite characteristic in certain orders and families. 7, 
is a warty growth on the epidermis, they are generally ab- 
normal developments produced by some irritation, 8, is an 
enlarged hair cell to show the streaming motion in vegetable 



VEGETABLE HISTOLOGY. 97 

protoplasm. To study this use a J-inch obj. and B ocular. 
This motion can only be studied while the hair cells are alive. 
It is very interesting to study this movement in protoplasm 
since it gives ocular proof that it has the power of motion. 
The only reasonable theory to account for this motion is Ber- 
thold's based on chemism as already explained. The arrows 
indicate the direction of currents but these directions are not 
fixed, they may change and the currents flow in opposite di- 
rections. Study these movements in hair cells of Primrose 
and other plants. 9, is an air space found beneath all 
stomata. The two guard cells, 10, are modified epidermal 
cells. They, however, contah chlorophyll and an elongated 
clear nucleus. Their function is to regulate the evaporation 
of moisture from plants. Stomata are structures peculiar to 
the under side of leaves, but are also found less abundantly 
on upper side and on stem, -petiole and other parts of plants. 
All the structures in fig. 2, are to be studied in other plants 
and compared with that of the cucumber. Water pores are 
found in many plants. They resemble stomata somewhat 
but differ from them in the fact that the guard cells are im- 
movable and the opening therefore is constant in size, also 
it is found that water instead of gas oozes from them. They 
are found at the extremities of veins near the upper margin 
of leaves. 



In fig. 3, the rind parenchyma 3, should be represented 
as extending to the epidermis wherever the stomata are found, 
Often it is found that the rind parenchyma cells just beneath 
the stomata begin to divide into oblong cells ; this division 
extends over into the adjoining collenchvma. Soon a menis- 
cus shaped layer of cells is formed called the cambium of 
lenticel. From this cambium are developed oblong, thin- 
walled, corky cells without chlorophyll. Finally these be- 
come so numerous as to rupture the epidermis at the stomata. 
These structure.- are called lenticels and appear to the 
naked eve as whitish spots distributed over the hark of 



98 VEGETABLE HISTOLOGY. 

Sainbucits niger for instance. To study these make careful 
surface and radial sections of these white spots and mount in 
water. Look for the cambium and superimposed loosely 
connected corky cells protruding through the rupture in the 
epidermis. The spaces between the loosely connected cells 
are filled with air thus admitting it to the inner tissue of the 
stem. Lenticels thus takes the place of stomata in the older 
stem where cork formation has begun. 

True cork tissues can be studied in the bark of many 
plants. Make a cross section of a small stem of Quercus of 
any cork bearing stem. 




a, epidermis ; b, cork cells ; c, cork cambium ; d, rind parenchy- 
ma ; e, typical sclerenchyma cells ; f and g, method of forming 
laticiferous tubes ; h, calcium oxalate crystals ; a, b, c, d, e, tip of 
fern rootlet ; x 180. 

The cork cells are formed from the cork cambium shown 
at c, fig. 4. The youngest cork ceils are colorless, the older 
yellow, and the oldest yellow-brown. Chloriodide of zinc 
stains them a yellow-brown, the younger darker than the 



VEGETABLE HISTOLOGY. 99 

older. There are no intercellular spaces ; cells appear rec- 
tangular, filled with air. Cork is also formed over the sur- 
face of wounds there serving to prevent the escape of cell 
sap. Cork is formed from collenchyma. c and upper layer 
of b in fig. 1, represents the under and upper parts of origin- 
al collenchyma cells. The layer of cork cells just beneath 
the epidermis is called the u phelloderm," and the cork cam- 
bium is generally called the u phellogen." Make a section 
through a this year's stem of Ribes nibrum in which cork 
formation has just begun. In it you can seen the first forma- 
tion of the phelloderm from the upper original layer of col- 
lenchyma. 

Many plants when wounded give out a milky fluid. It 
is only milky so far as consistency is concerned ; it may differ 
greatly in color and chemical composition in the different 
plants. This milky fluid is contained in a special tissue, the 
laticiferous tissue. This tissue is mostly found in the true 
parenchyma, especially on the sides of vascular bundles. 
Two kinds of milk tubes are distinguished, simple and com- 
plex. In the simple variety the tube consists of a single 
much elongated sometimes branching cell as in the Euphor- 
bias. The complex milk tube is formed by the coalescence 
of many cells as shown at f and g in fig, 4. This variety 
occurs in the Dandelion. Make longitudinal sections to study 
milk tubes. At h, fig. 4, are shown a few oxalate of calcium 
crystals. These are quite common though others may found. 

Tracheids are intermediate in structure between lignin 
cells and ducts. They differ from wood in having their 
walls less thickened, thus giving rise to pitted, spiral or 
ring like markings. Pitted tracheids are peculiar to pines. 
Make a longitudinal section of young stem, soak in alcohol 
to dissolve resin, and mount in water or dilute alcohol. 
Tracheids differ from ducts in that they do DOt become con- 
fluent end to end to form tube- ; each tracheid consists of a 
single elongated cell. Carefully study the pitted tracheids in 



100 VEGETABLE HISTOLOGY. 

both cross and longitudinal sections of pine stem. The pits 
appear as circular dots on the cell wall in the longitudinal 
section, facing toward the radial surface of section. 

This article on Vegetable Histology is only intended to 
give the student a start in the study of plant structure. Suf- 
ficient has been indicated to enable the student to study tissues 
in different plants and make comparisons. 

Finis. 



IN DEX. 



1 ] Microscopy 5-3-1 

l 2 Microscopy 5-6 

l 3 Brief History . 5-6 

2 2 Physics • 7 

l 3 Images 7-10 

l 4 Real 7 

2 4 Virtual 7 

2 3 Lenses 10 

1* Kinds 10 

2* Construction 10 

l 5 Crown Glass 10 

2' Flint Glass 10 

3 1 Mathematics 12-20 

l 5 Refraction by plane surfaces 13 

2 5 Refraction by inclined surfaces 14 

3 5 Index of Refraction 12-13 

l 6 Comparative 12 

2 6 Absolute 13 

4 5 Optic Center of Lens. 15-16 

5 5 Conjugate Foci 10 

6 5 Principal Focus 17 

7 8 Powers of Lenses 17 

8 5 Practical Problems 20 

3 2 Microscopes 20-34 

l 3 Simple 21-22 

1 ' Stanhope Magnifiers 21 

2 4 Coddington Lenses L > 1 

:;' Doublets 2] 

V Triblete 22 

_ ; Compound Microscopes 22-34 

l 1 Parts 22 32 



INDEX. 

J 5 Stand . . 22-23 

l 6 Jackson Model 22 

2 6 Ross Model 22 

2 5 Objectives 24 

l 6 Construction 24-32 

l 7 Wenham's Formula 27 

2 7 Other Combinations 27 

2 6 Aperture 2(3-27 

l 7 Air Angle 26 

2 7 Numerical 27 

3 6 Power 26 

l 7 High 26 

2 7 Low 26 

4° Immersion Objectives 26 

V Homogeneous 26 

2 7 Oil Immersion 26 

5 6 Properties 28-29 

l 7 Working Distance 28 

2 7 Defining Power 28 

3 7 Freedom from Aberration 29 

4 7 Penetrating Power 29 

5 7 Resolving Power 29 

3 8 Eyepieces or Ocuiars 27-28 

l fi Huyghenian 27 

2 6 Achromatic 28 

3 6 Solid 27 

4 5 Ajustments 30 

l 6 Fine 30 

2 6 Coarse 30 

5 5 Stage 30 

6 5 Substage 30-31 

7 5 Diaphragm 30 

l 6 Wheel 30 

2 6 Iris 30 

8 5 Mirror 30 

l 6 Plane 30 

2 6 Curved 30 



INDEX. iii 

2* Other Accessories 31-33 

l 5 Drawtube 29 

2 5 Nose Pieces 31 

3 5 Condensors 31 

4 5 Reflectors 

5 5 Microscope Tables 31 

6 5 Microscope Lamps : 31 

7 5 Micrometers * 33 

S 5 Camera Lucida 32 

3 4 Use and Care of Microscope 33-34 

2 1 Biology 35-81 

l 2 Study of Biology 35-40 

I 3 Necessary Material 41-44 

2* Starch 44-46 

l 4 Corn 44 

2 4 Wheat 44 

3 4 0at 44 

4 4 Potatoe 44 

3 3 Pollen 46-48 

4 3 Fermentation 48-50 

5 3 Yeast 58-60 

6 3 Amoeba 61-62 

7 3 Blood Corpuscles 63-64 

l 4 Red 63 

2* White 63-64 

8 a Cappillary Circulation 64 

9 3 Temporary Mounts C)5 

10 s Needle Preparations C)C)-()8 

IP Preparations for Microtome 68-72 

12 s Vegetable Tissue 72-74 

i3 a Algae 72-73 

14 :< Bone 74 75 

1 .V Insects 76-79 

L6 a Bacteria 79 81 

Genera] Advice 78-79 

Recipes B2 -83 



iv INDEX. 

Vegetable Histology 85-99 

l 1 Cell structure 85-87 

2 1 Micellae 87 

3 1 Protoplasm 87-89 

P Zell Granula 89 

5 1 Cell division 89-90 

6 1 Tissues 90-99 

l 2 ' Meristematic 90-91 

l 3 Dermatogen , 90 

2 3 Periblem 90 

3 3 Plerome 90 

2 2 Mature 91-99 

l 3 Vascular tissue 91-99 

2 3 Parenchyma 91-99 

3 3 Colienchyma 91 

4 3 Sclerenchyma . . 92 

5 3 Lignin 91-99 

6 3 Tracheids 99 

7 3 Sive tissue 90-91 

8 3 Cork 98 

9 3 Milk tissue 99 

10 3 Epidermal tissue 90 



